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  • 2020-2023
  • 1985-1989  (26)
  • 1965-1969  (32)
  • 1987  (26)
  • 1969  (28)
  • 1966  (4)
  • Cat
  • 1
    Electronic Resource
    Electronic Resource
    Prenatal development of the cat thyroid: immunohistochemical demonstration of calcitonin in the “C” cells (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 51-54 
    Details
    ISSN: 1432-0568
    Keywords: Development ; Thyroid “C” cell ; Cat ; Immunohistochemistry ; Calcitonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The presence of calcitonin in the cat thyroid was studied immunohistochemically in a series of gland development. the first positive cells are to be found on the 38th day of gestation, i.e. 1–2 days after level nine of ontogenetic development has been reached. The cytoplasm of these cells form only a narrow border round the nucleus. With advancing development the bumber of calcitonin-positive and its amount increases. From approximately the 50th day of prenatal development, the initially diffusely scattered, solitary calcitonin-positive cells are gradually replaced by groups of cells, which begin to occupy a characteristic position in relation to the follicular epithelium. The largest quantity of calcitonin-positive cells is found in foetuses about to be born. In non-pregnant adult cats, the incidence of immunohistochemically calcitonin-reactive cell is more sporadic and their distribution in the lobes of the thyroid is uneven.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325289
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  • 2
    Electronic Resource
    Electronic Resource
    An investigation of pulp capillaries and tight junctions between odontoblasts in cats (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 131-138 
    Details
    ISSN: 1432-0568
    Keywords: Capillaries ; Tooth pulp ; Tight junctions ; Odontoblasts ; Ultrastructure ; Mineralisation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative roles of capillaries and odontoblasts in the process of dentinogenesis and in pulp reactions to trauma and pathology are not clear. Contributing to the problem is the paucity of information on odontoblast —capillary relationships and tight junctions between odontoblasts. Using light microscopy the capillaries have now been examined in semithin transverse sections of perfusion fixed teeth at different positions in the long axis from the apical foramina to the pulp horns. Odontoblastic capillaries were prominent in the coronal and middle regions of canines and present at the same levels of incisors. In the pulp horns and just coronal to the pulp horns capillaries were all subodontoblastic but near the apex there were also a few odontoblastic capillary profiles. Transmission electron microscopy on ultrathin sections revealed that a high proportion of middle and coronal odontoblastic capillary profiles were fenestrated but subodontoblastic profiles coronal to the pulp horns were the most fenestrated. In a search for tight junctions in ultrathin sections some typical strands were observed between odontoblasts. The difficult of obtaining the latter evidence was explained by the cellular arrangement of the odontoblasts which differed markedly from an ideal parallel, apically coplanar arrangement. The results question the possibility that there is a direct exchange of materials between pulp capillaries and dentine in teeth of limited growth and provide a baseline for future experiments to test the permeability of the odontoblast layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572537
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  • 3
    Electronic Resource
    Electronic Resource
    Structural alterations in the spinal cord during progressive communicating syringomyelia. An experimental study in the cat (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 248-255 
    Details
    ISSN: 1432-0533
    Keywords: Experimental communicating syringomyelia ; Ependyma ; Spinal cord ; Cat ; Scanning electron microscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A hydrocephalic-hydromyelic condition was induced in adult cats by causing the closure of the lateral apertures with intracisternal injections of kaolin. After displaying the symptoms characteristic of increased intracranial pressure, which lasted about 10–14 days but varied somewhat in intensity from animal to animal, the cats recovered. From approximately the 2nd post-operative week onward, a distended central canal was revealed by ventriculography; subsequently cavities developed in the tissue of the cord that communicated with the canal. Most cavities were located dorsal to the canal. The surfaces of the distended canal and the cavities showed that in ventral areas the ependyma streched but remained intact, whereas in dorsal areas it ruptured, exposing the nerve fibers to the cerebrospinal fluid (CSF). In cats which had been hydrocephalic for up to 2 years the walls of the cavities were covered by gliotic scar tissue; the nerve fibers were no longer exposed directly to the CSF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691097
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  • 4
    Electronic Resource
    Electronic Resource
    Vestibular and optokinetic eye movements evoked in the cat by rotation about a tilted axis (1987)
    Springer
    Experimental brain research 66 (1987), S. 522-532 
    Details
    ISSN: 1432-1106
    Keywords: Off-vertical-axis rotation ; Eye movements ; Vestibulo-ocular reflex ; Optokinetic nystagmus ; Otoliths ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Horizontal and vertical eye movements were recorded from cats in response to either a) off-vertical axis rotation (OVAR) at a range of velocities (5–72 deg/s) and a range of tilts (0–60 deg) or b) horizontal (with respect to the cat) optokinetic stimulation (10–80 deg/s), also around a range of tilted axes (0–60 deg). The responses to stopping either of these stimuli were also measured: post-rotatory nystagmus (PRN) following actual rotation, and optokinetic after nystagmus (OKAN) following optokinetic stimulation. The response found during OVAR was a nystagmus with a bias slow-phase velocity that was sinusoidally modulated. The bias was dependent on the tilt and reached 50% of its maximum velocity (maximum was 73±23% of the table velocity) at a tilt of 16 deg. The phase of modulation in horizontal eye velocity bore no consistent relation to the angular rotation. The amplitude of this modulation was roughly correlated with the bias with a slope of 0.13 (deg/s) modulation/(deg/s) bias velocity. There was also a low-velocity vertical bias with the slow-phases upwardly directed. The vertical bias was also modulated and the amplitude depended on the bias velocity (0.27 (deg/s) modulation/ (deg/s) bias velocity). When separated from the canal dependent response, the build up of the OVAR response had a time constant of 5.0±0.8 s. Following OVAR there was no decline in the time constant of PRN which remained at the value measured during earth-vertical axis rotation (EVAR) (6.3±2 s). The peak amplitude of PRN was reduced, dependent on the tilt, reaching only 20% of its EVAR value for a tilt of 20 deg. When a measurable PRN was found, it was accompanied by a slowly-emerging vertical component (time constant 5.4±2s) the effect of which was to vector the PRN accurately onto the earth horizontal. OKN measured about a tilted axis showed no differences in magnitude or direction from EVAR OKN even for tilts as large as 60 deg. OKAN following optokinetic stimulation around a tilted axis appeared normal in the horizontal plane (with respect to the animal) but was accompanied by a slowly emerging (time constant 4.1±2 s) vertical component, the effect of which was to vector the overall OKAN response onto the earth horizontal for tilts less than 20 deg. These results are compared with data from monkey and man and discussed in terms of the involvement of the velocity storage mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270685
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  • 5
    Electronic Resource
    Electronic Resource
    Expression of “retinal” contrast gain control by neurons of the cat's lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 66 (1987), S. 589-596 
    Details
    ISSN: 1432-1106
    Keywords: Contrast gain control ; Lateral geniculate nucleus ; Temporal frequency ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This paper describes the temporal tuning of cells in the lateral geniculate nucleus of the cat (27 X cells, 51 Y cells) and how this changes with stimulus contrast. Drifting sinusoidal gratings of optimal spatial frequency were presented at 7 temporal frequencies (0.5, 1, 2, 4, 8,16 and 32 Hz) and 4 contrasts (10, 20, 40, 80%). For some cells response growth at all temporal frequencies was proportional to changes in contrast. Thus, their temporal tuning functions, on log-log axes, were displaced vertically with increasing contrast. This shift also largely characterizes the response to low temporal frequencies of the other neurons studied. For these other cells, however, responses to high temporal frequencies grew disproportionately large with increasing contrast generally causing their tuning functions to change shape. Typically the peaks of these functions shifted to higher frequencies at higher contrasts. Most of the X cells studied displayed behavior of the first type, while Y cells usually followed the second pattern. This qualitative impression was confirmed quantitatively. Cubic spline functions were fit to the temporal tuning functions obtained at different contrast levels and the peaks of the curves were extracted. X and Y cells preferred similar temporal frequencies at low contrast levels (X mean=8.1 Hz; Y mean=8.4 Hz) but Y cell values were significantly higher at higher contrasts (80%) (X mean= 12.0 Hz; Y mean=16.8 Hz). These contrast-dependent changes in the temporal characteristics of geniculate cells resemble those described for retinal ganglion cells by Shapley and Victor (1978 and subsequent). Thus, the gain control behavior of geniculate cells probably reflects the temporal properties of their retinal inputs with relatively little modification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270692
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  • 6
    Electronic Resource
    Electronic Resource
    Reduced binocularity in the noradrenaline-infused striate cortex of acutely anesthetized and paralyzed, otherwise normal cats (1987)
    Springer
    Experimental brain research 68 (1987), S. 593-605 
    Details
    ISSN: 1432-1106
    Keywords: Ocular dominance ; Plasticity ; Noradrenaline ; Cat ; Visual cortex ; Squint effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In anesthetized and paralyzed cats, the normal alignment of the visual axes is disturbed by paralysis of the eye muscles. Thus, the separation between paired receptive fields of binocular cells in visual cortex is increased (paralysis squint). This increased separation is normally tolerated by the majority of visuocortical cells, about 80% of them being binocularly driven (Hubel and Wiesel 1962). It was shown previously that neuronal plasticity in visual cortex can be enhanced in both normal adult cats (Kasamatsu et al. 1979) and kittens (Kuppermann and Kasamatsu 1984) by intracortical microinfusion of noradrenaline (NA). In the present study we tested whether the usual range of disparity produced by the paralysis squint is sufficient to induce ocular dominance changes in visual cortex of adult cats when the neuronal plasticity is enhanced by NA. NA was continuously infused into visual cortex throughout the experiments. The period of the paralysis squint varied from experiment to experiment between 9 and 47 h. We found: (1) These short periods were sufficient to produce a marked reduction in the proportion of binocular cells. (2) The proportion decreased linearly with increasing the duration of the squint period at a rate of 0.17 per 10 h up to about 22 h. (3) At longer durations the average binocularity remained at about 0.30 and could not be further reduced in the present paradigm. (4) The binocularity seemed to decrease with increasing separation of paired receptive fields. (5) Binocularity increased again toward the normal value after optical correction of the squint. (6) The amount of increased binocularity was linearly correlated with the duration of the period after the squint correction. (7) The binocularity increased at a rate of 0.18 per 10 h, reaching the normal value in less than 30 h. We thus concluded that if visuocortical plasticity is maintained at a high level through the continuous infusion of NA it is possible to change the ocular dominance distribution in the mature visual cortex by manipulations of the alignment of the visual axes even in the acutely anesthetized and paralyzed condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249802
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  • 7
    Electronic Resource
    Electronic Resource
    Receptive field properties of cells in area 19 of the cat (1987)
    Springer
    Experimental brain research 65 (1987), S. 549-558 
    Details
    ISSN: 1432-1106
    Keywords: Area 19 ; Sinusoidal grating ; End-zone inhibition ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recorded extracellularly from single cells in area 19 of the cat for the purpose of providing a quantitative description of response characteristics. A prominent feature of this area is a high incidence of cells that are end-stopped. Drifting sinusoidal gratings were used to determine spatial and temporal characteristics of the discharge region. In addition, we have conducted independent tests to characterize end zones of receptive fields. When a grating patch was used to stimulate the discharge region alone, all of the cells showed a band-pass spatial frequency tuning characteristic. The optimal spatial frequency ranged from 0.1 to 1.13 cycles/deg, and the distribution had a peak at 0.4 cycles/deg. The bandwidth at half peak amplitude ranged widely from 0.7 to 3.3 octaves (mean 2.0 octaves). When gratings were also presented to the end zones, responses to stimulation of the central region were suppressed. The surround was phase-insensitive in that the relative phase between the grating in the two regions generally did not affect the strength of the suppression. To determine spatial characteristics of the end-zone inhibition, the spatial frequency of the end-zone grating was changed while that for the central pattern was fixed. All cells showed a bandpass characteristic for end-zone inhibition, but in each case, the tuning width was broader than that for excitation. The mean spatial frequency bandwidth of end-zone inhibition was 2.7 octaves. The peak of the inhibition generally coincided with the peak of the excitatory spatial frequency tuning of the discharge center. Considered together, these results show that neurons in area 19 share common properties with those in areas 17 and 18, but they exhibit phase-insensitve end-zone inhibition more frequently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235978
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  • 8
    Electronic Resource
    Electronic Resource
    Automatic postural responses in the cat: responses of proximal and distal hindlimb muscles to drop of support from a single hind- or forelimb (1987)
    Springer
    Experimental brain research 65 (1987), S. 527-537 
    Details
    ISSN: 1432-1106
    Keywords: Postural reflexes ; Unexpected postural perturbations ; Electromyographic activity ; Hindlimb muscles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cats respond to drop of the support from beneath a single limb with the “diagonal stance response” (Coulmance et al. 1979). They load the limbs on the diagonal opposite to the one containing the dropped limb and unload the third supporting limb in the diagonal containing the dropped limb. Characteristic biomechanical delays in limb motion and in vertical force changes imposed upon the limbs are observed. These delays range from 30 to 45 ms, depending upon the location of the dropped limb. This study describes the kinematics of the “diagonal stance response” and the activation of selected agonist-antagonist muscle pairs acting on the joints of the hindlimb during the response. Proximal and distal hindlimb muscles respond to perturbations in groups that are appropriate to the vertical forces imposed upon the limb. When the hindlimb containing the recording electrodes is loaded by drop of the contralateral hindlimb or the ipsilateral forelimb medium latency (25–45 ms) EMG responses occur in the extensors. This response serves to stiffen the limb against the increased vertical force of loading. A similar response is observed when the hindlimb is reloaded after being dropped. In this case, however, short latency responses precede the medium latency responses in muscles that are passively stretched by the limb drop. When drop of the diagonal forelimb unloads the hindlimb containing the electrodes, medium latency responses are observed in the distal hindlimb flexors, which indicates that the unloading is evoked in part by active lifting of the limb. In most cases, the medium latency responses precede or are coincident with the changes in force imposed on the limb, suggesting that the observed responses are centrally programmed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235976
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  • 9
    Electronic Resource
    Electronic Resource
    Neuronal dynamics in the visual corticothalamic pathway revealed through binocular rivalry (1987)
    Springer
    Experimental brain research 66 (1987), S. 10-20 
    Details
    ISSN: 1432-1106
    Keywords: Corticothalamic feedback ; Binocular rivalry ; Lateral geniculate ; Vision ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit activity was recorded from principal cells in the A-laminae of the cat dorsal lateral geniculate nucleus (dLGN). A steady state pattern of afferent activation was induced by presenting a continuously drifting square wave grating of constant spatial frequency to the eye (the dominant eye) that provided the excitatory input to the recorded cell. Intermittently, a second grating stimulus was presented to the other, nondominant, eye. In most neurones nondominant eye stimulation led to inhibition of relay cell responses. The latency of this suppressive effect was unusually long (up to 1 s) and its intensity and duration depended critically on the similarity between the gratings that were presented to the two eyes. Typically suppression was strongest when the gratings differed in orientation, direction of movement and contrast and when the nondominant eye stimulus was moving rather than stationary. Ablation of visual cortex abolished these long latency and feature-dependent interferences. We conclude that the visual cortex and the corticothalamic projections are involved in the mediation of these interocular interactions. We interpret our results as support for the hypothesis that corticothalamic feedback modifies thalamic transmission as a function of the congruency between ongoing cortical activation patterns and afferent retinal signals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236196
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  • 10
    Electronic Resource
    Electronic Resource
    Responses of bradykinin sensitive tooth-pulp driven neurons in cat cerebral cortex (1987)
    Springer
    Experimental brain research 66 (1987), S. 435-439 
    Details
    ISSN: 1432-1106
    Keywords: Bradykinin ; Tooth-pulp ; Cortical neuron ; Coronal gyrus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The properties of single cortical neurons responding to electrical stimulation of the tooth-pulp and to intrapulpal application of bradykinin were studied in the cat. The activities of tooth-pulp driven neurons (TPNs) were recorded from the middle and anterior parts of the coronal gyrus of the cerebral cortex. Bradykinin-sensitive tooth-pulp driven neurons (BK-TPNs) were located in layer IV of area 3b of the anterior part of the coronal gyrus. These neurons had a large cutaneous oro-facial receptive field and received a nociceptive input from the facial skin as well as from the tooth-pulp. The BK-TPNs had a higher threshold and longer latency to electrical stimulation than TPNs insensitive to bradykinin (non BK-TPNs). These findings suggest that BK-TPNs in this cortical area may be involved in sensory processing of noxious information from trigeminal regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243318
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  • 11
    Electronic Resource
    Electronic Resource
    Responses of cat preoptic neurons to stimulation of the medial frontal cortex and the medial basal hypothalamus (1987)
    Springer
    Experimental brain research 66 (1987), S. 555-564 
    Details
    ISSN: 1432-1106
    Keywords: Preoptic region ; Frontal cortex ; Medial basal hypothalamus ; Electrophysiology ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of single preoptic neurons to electrical stimulation of the medial frontal cortex, the mediobasal hypothalamus (MBH) and the medial forebrain bundle (MFB) were recorded in anaesthetised cats. Single pulse stimulation of the medial frontal cortex orthodromically drove 96 otherwise quiescent preoptic neurons, which were found more frequently in the dorsal preoptic region, inhibited 53% of the spontaneously active preoptic neurons and excited 16%. Testing of cortically influenced preoptic neurons with MBH or MFB stimulation resulted in antidromic invasion of 6% (MBH) and 9% (MFB). Convergence of orthodromic inputs from medial frontal cortex and MBH was detected in 78% of spontaneously active preoptic neurons, and three-way convergence including input from MFB was noted in 17% of neurons tested with all stimulators. Some cortex-responsive neurons were found to also respond to vaginal or anal probing, paw squeezing and haemorrhage. The role of this input to the preoptic region from medial frontal cortex remains to be elucidated, but may include neuroendocrine, behavioural and homeostatic functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270688
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  • 12
    Electronic Resource
    Electronic Resource
    Branching cortical neurons in cat which project to the colliculi and to the pons: a retrograde fluorescent double-labeling study (1987)
    Springer
    Experimental brain research 67 (1987), S. 1-15 
    Details
    ISSN: 1432-1106
    Keywords: Corticopontine collaterals ; Corticotectal neurons ; Cortex ; Cat ; Fluorescent tracers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fluorescent double-labeling technique has been used to determine whether the corticopontine and the corticotectal fibers in the cat are derived from two different sets of neurons or whether they are derived from branching neurons which distribute collaterals to the pontine grey and the colliculi. After unilateral DY.2HCl injections in the pontine grey and FB injections in the ipsilateral colliculi, large numbers of FB-DY.2HCl double-labeled neurons were present in the cortex of the ipsilateral hemisphere. However, the labeled neurons in its rostral part may have represented pyramidal tract neurons which were labeled retrogradely because their fibers descended through the DY.2HCl injection area. Therefore, also DY.2HCl injections were made in the pyramid (i.e. caudal to the pons) and the cortical pyramidal tract area, containing the retrograde DY.2HCl-labeled neurons, was delineated. In the rest of the experiments only the DY.2HCl-labeled neurons in the caudal two thirds of the hemisphere (outside the pyramidal tract area) were taken into account because only these neurons could, with confidence, be regarded as corticopontine neurons. In some anterograde HRP transport experiments the trajectories of the corticotectal and the corticopontine fibers were visualized. On the basis of the findings the DY.2HCl injections in the pontine grey were placed such that they could not involve any of the corticotectal fibers passing from the cerebral peduncle to the colliculi. Thus artifactual doublelabeling of cortical neurons was avoided. However, also under these circumstances many double-labeled neurons were present in the caudal two thirds of the hemisphere. This led to the conclusion that in the cat a large proportion of the corticopontine neurons in the caudal two thirds of the hemisphere represent branching neurons which also distribute collaterals to the colliculi. The parietal (anterior part of the lateral gyrus, middle and posterior suprasylvian gyri) and the cingulate areas together contained three quarters of all labeled corticopontine neurons outside the pyramidal tract area. In the parietal areas roughly 25% of them were double-labeled and in the cingulate area 14%. However, in the visual areas 18 and 19 a much larger percentage (30–60%) was doublelabeled. In a recent study from our laboratory it was found that in the cat the pyramidal tract fibers distribute an abundance of collaterals to the pontine grey. Therefore, a large proportion of all corticopontine connections in this species appear to be established by branching neurons which also distribute fibers to other cell groups in the brain stem and the spinal cord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269447
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  • 13
    Electronic Resource
    Electronic Resource
    Detection latencies of X and Y type cells of the cat's dorsal lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 65 (1987), S. 703-706 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Electrophysiology ; Lateral geniculate cells ; Signal detection ; Visual latencies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The latencies of visually-evoked responses from X- and Y-type neurons of the cat's dorsal lateral geniculate nucleus were measured in a manner that takes account of the inherent variability of discharge in these cells. Latencies measured in this way vary from trial to trial in one cell (and also between cells) by tens to as much as hundreds of milliseconds. This variability in the time for generation of reliable responses suggests that the much emphasized conduction advantage of the Y pathway plays a minor role in the detection of visual stimuli by the cat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235998
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  • 14
    Electronic Resource
    Electronic Resource
    Convergent inputs from articular, cutaneous and muscle receptors onto ascending tract cells in the cat spinal cord (1987)
    Springer
    Experimental brain research 66 (1987), S. 479-488 
    Details
    ISSN: 1432-1106
    Keywords: Joint ; Spinal cord ; Pain ; Ascending tracts ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1.Responses were recorded from 160 ascending tract cells in segments L4 to L6 of the spinal cord in chloralose anaesthetized, spinalized cats. The tract cells were identified by antidromic activation following stimulation of pathways in the lateral and ventral funiculi at the level of the spinal cord transection at the thoracolumbar junction. Axonal conduction velocities ranged from 9 to 114 m/s. 2. A sample of 152 of the neurones examined could be subdivided according to the distribution of their receptive fields into 49 cells activated just from receptors located in skin (“s” cells), 17 neurones excited by receptors in deep tissues (“d” cells), 15 units with a convergent input from receptors in skin and deep tissues (“sd” cells), and 25 neurones with a convergent input from the knee joint and either skin (“sj” cells), deep tissues (“dj” cells) or both (“sdj” cells). No receptive fields could be demonstrated for the remaining 46 neurones. 3. “S” and “sj” cells were found almost exclusively in the dorsal horn, whereas many “d”, “sd”, “sdj” and “dj” units were in the ventral horn. Almost all of the cells that lacked receptive fields were in the ventral horn or intermediate grey. 4. Ninety-one of 158 cells (56%) demonstrated no background activity. Of these, 43 cells (27%) lacked receptive fields. Many of the silent neurones were in the ventral horn, but some were in the dorsal horn. Of 25 cells having knee joint input, 18 (72%) had background activity. 5. All of the neurones that had a receptive field in the knee joint also had a convergent input from receptors in other tissues. In 3 cases, there was a receptive field in the skin over the foot (“sj” cells). For 16 cells, receptive fields included not only the knee joint but also skin and deep tissue (“sdj” cells). Usually, the cutaneous receptive field was near the knee joint, but sometimes it was remote, such as on the foot. The deep receptive fields were chiefly in the muscles of the thigh and/or leg. For 6 “dj” cells, the receptive fields included not only the knee joint but also deep fields like those of “sdj” cells. 6. Cutaneous receptive fields were classified as “low threshold” (cells excited best by innocuous intensities of mechanical stimulation), “wide dynamic range” (cells activated by weak mechanical stimuli, but the best responses were to noxious stimuli) or high threshold (innocuous stimuli had little effect, but noxious mechanical stimuli produced a vigorous discharge). Similarly, stimulation of the knee joint with weak mechanical stimuli could excite some neurones, while others could be activated by weak or strong articular stimuli but were excited best by noxious stimuli, and still other neurones were activated by knee joint stimuli only if the intensity was noxious. 7. In several instances, contralateral receptive fields were noted. These were generally in deep tissue or in the knee joint. 8. It was concluded that many of the responses to articular stimulation of the spinal cord ascending tract cells examined in this study could have been mediated by the fine afferent fibres that supply the knee joint. Although further work will be required to determine which particular ascending tracts transmit nociceptive information concerning the knee joint, it can be proposed that many of the responses demonstrated here were likely to play a role in either joint pain of in triggering responses associated with joint pain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270680
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  • 15
    Electronic Resource
    Electronic Resource
    Lateral excitation in the cat lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 67 (1987), S. 291-298 
    Details
    ISSN: 1432-1106
    Keywords: Lateral inhibition ; Lateral excitation ; Cat ; Dorsal lateral geniculate nucleus ; GABA ; Silent synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Visual responses were elicited by global phase reversal stimuli in cells of the cat dorsal lateral geniculate nucleus (dLGN) after small retinal lesions had been centered on each receptive field. After acute lesions of different sizes exclusively lateral inhibition was found. When GABAergic inhibition was blocked by continuous microiontophoretic application of bicuculline lateral excitation emerged in dLGN cells partially deafferented by small and medium size acute retinal lesions, but not in those affected by large lesions. This indicates the presence of excitatory retinal inputs at the periphery of the dLGN cell dendrites which are normally suppressed by strong, long-ranging lateral inhibitory processes. After chronic deafferentation, the remaining excitatory inputs increase in effectiveness and lateral excitation is seen without blockade of inhibition. The maximal lateral spread of excitation (300 μm) in the dLGN is distinctly smaller than the extent of lateral inhibition (1000 μm).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248550
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  • 16
    Electronic Resource
    Electronic Resource
    Automatic postural responses in the cat: responses of distal hindlimb muscles to paired vertical perturbations of stance (1987)
    Springer
    Experimental brain research 68 (1987), S. 477-490 
    Details
    ISSN: 1432-1106
    Keywords: Postural reflexes ; Unexpected postural perturbations ; Electromyographic activity ; Motor control ; Hindlimb muscles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The active components of the quadrupedal diagonal stance response to rapid removal of the support from beneath a single limb were studied in cats to further define the mechanisms that trigger and generate the response. We recorded EMG activity from lateral gastrocnemius and tibialis anterior muscles in awake, behaving cats while they stood on an hydraulic posture platform. By dropping the support from beneath a single limb, we evoked the diagonal stance response, with its characteristic changes in vertical force and EMG patterns. As the animal responded to this drop, a second perturbation of posture was then presented at intervals of 10 to 100 ms following the first. This second perturbation, which consisted of dropping the support from beneath the two limbs that were loaded as a result of the initial limb drop, made the first response biomechanically inappropriate. The EMG responses observed in both muscles during paired perturbations were triggered by the somatosensory events related to the perturbations. Muscle responses that were appropriate for the first perturbation always occurred with amplitudes and latencies similar to control trials. This was true even when the second perturbation occurred 10–20 ms after the first, that is, when this perturbation either preceded or was coincident with the response to the initial limb drop. The EMG responses that were normally associated with the second perturbation were delayed and/or reduced in amplitude when the time interval between perturbations was short. As the inter-perturbation interval was lengthened beyond 60–100 ms, however, EMG responses to the second perturbation were unaffected by the occurrence of the first perturbation. When the hindlimb containing the recording electrodes was dropped as part of the second perturbation, a myotatic latency response was observed in tibialis anterior. The amplitude of this response to the second perturbation was greater than controls when this displacement was presented during the period between initiation of the first perturbation and execution of the response to it. When the second displacement was presented after execution of the first response began, the amplitude of the myotatic response was reduced below control levels. While the results do not preclude the possibility that these “automatic” postural responses are segmental or suprasegmental reflexes, they support the hypothesis that the active component of the response to drop of the support beneath a single limb is centrally programmed and that the appropriate response can be riggered very rapidly by the somatosensory information signalling the perturbation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249792
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  • 17
    Electronic Resource
    Electronic Resource
    The pattern of ocular dominance columns in flat-mounts of the cat visual cortex (1987)
    Springer
    Experimental brain research 68 (1987), S. 661-666 
    Details
    ISSN: 1432-1106
    Keywords: Visual cortex ; Ocular dominance columns ; Flat-mount ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ocular dominance (OD) columns in the cat visual cortex were visualized with autoradiography after intravitreal injection of (3H)proline. Extending previous studies, a flat-mount technique was applied that enabled the analysis of the distribution of label throughout extensive regions of the visual cortex without requiring reconstructions from serial sections. OD-columns were confined to layer IV and consisted of isolated patches and short bands. The latter were parallel to each other and regularly spaced, the main trajectory being orthogonal to the 17/18 border. This pattern of the geniculo-cortical terminals was similar in the hemispheres ipsi- and contralateral to the injected eye. The mean periodicities of the OD-bands were virtually identical in the two hemispheres of the same animal: 850 μm and 830 μm in cat D1 and 770 μm and 800 μm in cat D2. However, the ipsilateral OD-columns appeared smaller, more heavily labeled and more sharply delineated than the contralateral columns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249809
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  • 18
    Electronic Resource
    Electronic Resource
    Enhancement of the responses of ascending tract cells in the cat spinal cord by acute inflammation of the knee joint (1987)
    Springer
    Experimental brain research 66 (1987), S. 489-499 
    Details
    ISSN: 1432-1106
    Keywords: Joint ; Pain ; Inflammation ; Spinal cord ; Ascending tracts ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Recordings were made from 16 ascending tract cells in the spinal cords of anaesthetized, spinalized cats before and after an acute arthritis was produced by injection of kaolin and carrageenan into the knee joint. 2. The responses tested routinely were to passive flexion of the knee, an innocuous movement. In some cases, responses to other movements were also tested, and changes in background discharge rates were monitored. 3. Control recordings for a period of 1 h or in 3 cases of 3 h indicated that the responses to flexion were reasonably stationary. 4. Four tract cells that initially showed little or no response to flexion of the knee joint developed large responses within 1 to 2 h after inflammation of the joint. 5. Another 9 cells were tested that had responses to flexion of the knee joint prior to inflammation. In 6 cases, inflammation produced enhanced static or transient responses. In 2 cases, the effect of flexion was initially inhibitory or variable, but after inflammation these cells showed large excitatory responses. In the other case, inflammation had no effect. Background discharges were increased by inflammation in 6 of these 9 cells. 6. The effect of inflammation of the knee joint was tested on 3 tract cells that had no clearly defined receptive field in the knee. In 1 case, a response developed to knee flexion after acute inflammation was produced. In the other 2 cases, there were initially responses to knee flexion, but these were unchanged by inflammation. 7. Two of the cells tested had bilateral receptive fields in or around the knee joints. Inflammation of one knee joint enhanced the responses to flexion of the same but not of the contralateral knee in one case but greatly increased the responses to flexion of both knees in the other case. 8. Injections of prostaglandin (PGE2) caused an enhancement of the responses to knee flexion beyond that caused by inflammation in 5 of 7 cases. One cell whose responses to flexion of the knee were unaffected by inflammation showed inhibitory responses to prostaglandin injections into the inflamed knee joint. 9. The effects of inflammation on the responses of ascending tract cells of the spinal cord appear to serve as a useful neural model of the events responsible for the development of arthritic pain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270681
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  • 19
    Electronic Resource
    Electronic Resource
    Synaptic organization of olfactory inputs and local circuits in the entorhinal cortex: a current source density analysis in the cat (1987)
    Springer
    Experimental brain research 67 (1987), S. 615-622 
    Details
    ISSN: 1432-1106
    Keywords: Entorhinal area ; Current source density ; Olfactory afferents ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of the olfactory afferents within the ventrolateral part of the entorhinal cortex (EC) was studied by means of field potentials evoked by stimulation of the olfactory bulb (OB) and the olfactory cortex (PPC). Depth profiles of the field potentials evoked by OB or PPC stimulation were studied using current source density analysis. After OB or PPC stimulation an early superficial sink-deep source configuration was found, which some time later reversed into a superficial source-deep sink. Both OB and PPC activated mainly the superficial dendrites of the cells of layers II and III. In layers II and III evidence for strong recurrent inhibition was found, using double pulse stimulation. The results indicate that there exists a common basic design of the synaptic organization of the olfactory areas of the base of the brain extending to the EC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247292
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  • 20
    Electronic Resource
    Electronic Resource
    Direct projections from Ammon's horn to the septum in the cat (1987)
    Springer
    Experimental brain research 68 (1987), S. 179-188 
    Details
    ISSN: 1432-1106
    Keywords: Ammon's horn ; Hippocampus ; Septum ; Dentate gyrus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Direct projections from Ammon's horn to the septum were studied in the cat by the anterograde tracing method after injecting WGA-HRP (wheat germ agglutinin-horseradish peroxidase conjugate) into Ammon's horn. The results were further confirmed by the retrograde WGA-HRP method after injecting WGA-HRP into the septum. Pyramidal neurons in fields CA1, CA2 and CA3 were observed to send their axons ipsilaterally to the lateral septal nucleus; the septal parts of the hippocampus sent projection fibers to the dorsomedial portions of the lateral septal nucleus via the medial aspects of the subcallosal fornix, while the hippocampal regions successively more proximal to the temporal pole sent projection fibers to progressively more ventrolateral portions of the lateral septal nucleus via more lateral aspects of the subcallosal fornix. It was also found that the septal parts of fields CA1, CA2 and CA3 sent projection fibers bilaterally to the dorsomedial aspects of the lateral septal nucleus. Field CA4 appeared to send projection fibers only sparsely, if at all, to the medial septal nucleus. The rudimentary parts of the hippocampal formation, taenia tecta and indusium griseum, were found to have reciprocal ipsilateral connections with the dorsal portions of the lateral septal nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255243
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  • 21
    Electronic Resource
    Electronic Resource
    Binocular interaction in the dorsal lateral geniculate nucleus of the cat (1987)
    Springer
    Experimental brain research 68 (1987), S. 305-310 
    Details
    ISSN: 1432-1106
    Keywords: Binocular interaction ; Lateral geniculate nucleus ; Cat ; Retinal disparity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have investigated binocular interaction in the dorsal lateral geniculate nucleus (LGN) of the cat. Neurons were recorded extracellularly during visual stimulation with sinusoidal gratings which were presented at different interocular phases (disparities). The large majority of cells (91%) exhibited some type of binocular interaction. For 75% and 16% of the total number of cells, the binocular interaction was inhibitory or facilitatory, respectively. For the remaining 9% of cells, no interaction was evident. In marked distinction from visual cortex, the facilitatory and inhibitory interactions in the LGN are independent of the relative interocular phase of the patterns. Neurons in the LGN are therefore insensitive to the stereoscopic depth cue, retinal disparity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248796
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  • 22
    Electronic Resource
    Electronic Resource
    Processing of interaural time and intensity differences in the cat inferior colliculus (1987)
    Springer
    Experimental brain research 68 (1987), S. 379-392 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Inferior colliculus ; Single cell recording ; Binaural hearing ; Time/intensity trading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Binaural neurones were recorded in the central nucleus of the cat inferior colliculus and were stimulated with tone and noise bursts. Closed field sound systems were used to produce independent interaural time (ITD) and intensity (IID) differences. Particular attention was paid to high frequency (above 2 kHz) cells. 2. Three main types of binaural neurone were found: High frequency excitatory-inhibitory neurones (EI cells), excited by input from the contralateral ear and inhibited by ipsilateral input, high frequency excitatory-excitatory cells (EE cells), excited by inputs from either ear and low frequency cells sensitive to interaural phase differences (IPD cells). 3. The EI cells had characteristics similar to those of IE cells in the contralateral lateral superior olive. They were sensitive to envelope ITDs (most cells) and IIDs (all cells) favouring the contralateral ear. The response of these cells increased with increasing contra lead ITDs or contra loud IIDs up to values well outside the physiological range. 4. Low frequency binaural cells were sensitive to interaural phase differences (IPDs). The peak response was often in the contralateral physiological range and the response was unaffected by IIDs. 5. Many high frequency EE cells were sensitive to envelope ITDs. These units were relatively unaffected by IID. Although the ITD sensitivity of these cells was generally less than that of the IPD cells, the peak response of the ITD curve was also often in the contralateral physiological range. 6. Some of the high frequency EI and EE cells were sensitive to ongoing time differences (OTDs) in white noise signals, i.e. they showed ITD response curves to carrier only shifted noise bursts. 7. The EI cells often showed recovery from inhibition at large ipsilateral lead. This tendency was increased as the sound pressure level on the inhibitory side was lowered and by the use of click stimuli. Similarly, cycles of suppression could be seen to follow excitation in some EE cells. The time course of these effects was in the order of hundreds of μs. 8. Binaural characteristics (degree of ITD, IID or OTD sensitivity) showed considerable interunit variation within each cell type. These variations were also affected by signal type (tone or noise bursts) and did not appear to be correlated with best frequency, nature of the tuning curve or PSTH type. We suggest that the time course of the inhibitory and excitatory effects at each unit (and its interaction with the signal type) determines the type of ITD response and that this time course varies from cell to cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248803
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  • 23
    Electronic Resource
    Electronic Resource
    Effects of monocular strobe rearing on kitten striate cortex (1987)
    Springer
    Experimental brain research 68 (1987), S. 525-532 
    Details
    ISSN: 1432-1106
    Keywords: Cat ; Visual cortex ; Stroboscopic exposure ; Monocular experience ; Motion deprivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monocular deprivation in kittens does not lead to an ocular dominance shift in striate cortex if the visual stimuli do not contain contours. In the present study we sought to find out whether an ocular dominance shift is produced if the visual environment does contain contours but is devoid of motion. Six kittens were reared with one eye occluded in a visual environment that was lit only by the light of a stroboscope (2 flashes per sec). Exposure was started at 5–6 weeks of age after dark-rearing from birth and extended until 8–12 weeks of age for 8 h per day. The rest of the time was spent in total darkness. Thus, the animals were completely deprived of vision in one eye, while the other eye experienced only stationary flashing contours. Single units in area 17 of these animals were studied and compared to normally reared cats. In all six animals ocular dominance was clearly shifted towards the eye with strobe experience. The ocular dominance shift showed, however, the following interdependencies with other parameters: neurones that responded to stationary flashing test stimuli were nearly always dominated by the strobe eye; neurones that responded only to moving bars or edges remained binocular. In the normal control animals the ocular dominance distribution was similar for both groups of cells. Track analysis according to cortical lamination revealed that neurones in infragranular layers consistently showed a weaker OD shift towards the strobe eye than neurones in supragranular layers (including layer 4). Response latencies to stationary flashing stimuli were significantly shorter in the strobe-reared animals than in the normal controls. Orientation tuning was normal in all animals. Directional tuning was reduced after monocular strobe experience, but not by the same amount as described after binocular strobe rearing. The present results demonstrate that monocular visual experience reduced to stationary flashing contours is sufficient to produce on ocular dominance shift in striate cortex. This adds further support to existing notions about the role of nervous activity for changes in cortical connections. Cortical responses to afferent stimulation and the resulting correlated activation of pre- and postsynaptic neurones seem to be a prerequisite for a stabilization of synaptic connections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249796
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  • 24
    Electronic Resource
    Electronic Resource
    Tonotopic organization in the medial geniculate body (MGB) of lightly anesthetized cats (1987)
    Springer
    Experimental brain research 69 (1987), S. 24-42 
    Details
    ISSN: 1432-1106
    Keywords: Medial geniculate body ; Tonotopic organization ; Single unit pairs ; Frequency selectivity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the medial geniculate body (MGB) of nitrous oxide anesthetized cats, the pars lateralis (PL) was the only nucleus to show a clear topographic arrangement of its neurons according to their characteristic frequency (CF). When compared to barbiturate anesthetized cats (Imig and Morel 1985a), the tonotopic organization in PL appeared less strict and was characterized by a significant local CF disparity. Furthermore, the degree of tonotopic organization varied along the rostrocaudal axis of the nucleus: it was lower in its caudal than in its rostral half. In the pars ovoidea, the rostral half of the pars magnocellularis (PM) and the suprageniculate nucleus, CF sequences and quantitative evaluations of the tonotopicity indicated the presence of some degree of tonotopic organization which was lower than in PL. No such organization was observed in the caudal part of PM nor in the ventrolateral nucleus, while in the dorsal nucleus, the proportion of toneresponding units was too low for a significant analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247026
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  • 25
    Electronic Resource
    Electronic Resource
    The effects of CO2 and fixed acid on the O2-Hb affinity of rabbit and cat blood (1987)
    Springer
    Pflügers Archiv 408 (1987), S. 451-457 
    Details
    ISSN: 1432-2013
    Keywords: O2-Hb affinity ; Bohr effect interaction ; CO2 Bohr effect ; Fixed acid Bohr effect ; Rabbit ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The action of respiratory and metabolic acid-base disturbances on the O2-Hb affinity was studied in rabbits and cats. Blood samples of both species were exposed to in vitro pH-changes, which were either achieved by variation ofPCO2 (2.8–8.3 kPa) at constant lactic acid concentration, or by addition of lactic acid (5–14 mmol·l−1) at constantPCO2. ThePO2 at halfsaturation (P50) and the Hill'sn were determined from O2-Hb dissociation curves (ODC) in a range between 20 and 80% SO2. Under standard conditions (T=331 K,PCO2=5.33 kPa, pH=7.4), the average P50 value was 4.66±0.05 kPa in rabbits, that is slightly higher than reported by others, and 5.17±0.03 kPa in cats. The average values of Hill'sn were 2.91±0.02 and 2.95±0.03 for rabbits and cats, respectively. When plasma pH was varied by CO2, the resulting classical CO2 Bohr factor φCO2=ΔlgP50/ΔpH50 was distinctly higher in cats (−0.560±0.006,n=25) than in rabbits (−0.504±0.014,n=22), although in the latter species being even higher than reported elsewhere. Concomitant metabolic acidosis did not significantly affect φCO2, but shifted the P50 at a given plasma pH to lower values. Substitution of lactic acid with equimolar amounts of sodium lactate left both φCO2 and P50 unchanged. When plasma pH was varied by lactic acid (LA), the resulting fixed acid Bohr factors φLA were similar for cats (−0.420±0.016,n=21) and rabbits (−0.427±0.010,n=18), and not influenced by additional respiratory acidosis. Concomitant respiratory acidosis, however, shifted the P50 at a given plasma pH to higher values. The deviation of lgP50 from that under standard conditions (lgP50st) induced by both, respiratory and metabolic acid-base changes, can generally be expressed by Eqs. (1) or (2) (1) $$1gP_{50} - 1gP_{50} st = \varphi CO_2 \left( {pH - 7.4} \right) - \left( {\varphi CO_2 - \varphi LA} \right) \cdot \left[ {pH\left( {LA} \right) - 7.4} \right]$$ (2) $$1gP_{50} - 1gP_{50} st = \varphi LA\left( {pH - 7.4} \right) + \left( {\varphi CO_2 - \varphi LA} \right) \cdot \left[ {pH\left( {CO_2 } \right) - 7.4} \right].$$ Thereby, the first term considers the total pH-deviation, irrespective of its origin, and the second term represents the metabolic (1) or the respiratory (2) correction. For practical use and within the physiological range of plasma pH (7.2–7.6), φCO2 and φLA are assumed to be additively linked and to be independent of pH. Once these factors are determined for a given species, together with the buffer capacity for CO2, they provide sufficient data to estimate fairly accurately the position of the ODC. This is particularly important for in vivo conditions where respiratory and metabolic acid-base disturbances often occur simultaneously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585068
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  • 26
    Electronic Resource
    Electronic Resource
    Responses of sacral visceral afferents from the lower urinary tract, colon and anus to mechanical stimulation (1987)
    Springer
    Pflügers Archiv 410 (1987), S. 296-303 
    Details
    ISSN: 1432-2013
    Keywords: Sacral visceral afferents ; Pelvic nerve ; Urinary bladder ; Urethra ; Colon ; Anus ; Functional properties ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The discharge characteristics of sacral visceral afferents supplying the urinary bladder, urethra, colon and anus to mechanical stimuli were analyzed in the anaesthetized cat. The stimuli used were passive distension (urinary bladder, colon), isovolumetric contraction (urinary bladder), movements of the urethral catheter and mechanical shearing stimuli (mucosal skin of the anal canal). (1) In total 245 afferent units which projected in the pelvic nerve were isolated from the sacral dorsal roots. From one of the following organs, urinary bladder, colon, urethra and anus 117 afferent units were activated. By these stimuli from the bladder, urethra and anus 122 afferent units could not be activated, and as far as tested also not from the colon; in 6 afferent units the classification was unclear. (2) Afferent units from the urinary bladder and the colon responded consistently to passive distension of the respective organ. The units from the urinary bladder showed graded responses at intraluminal pressures of about 10–70 mm Hg and responded also to isovolumetric contractions of the organ. The thresholds of the units from the bladder to passive distension and contraction varied from about 5 to 20 mm Hg intravesical pressure. (3) The afferent units from the urethra and the anus did not react or showed some weak phasic and irregular responses to distension and contraction applied to the urinary bladder or to distension of the colon. They were consistently excited by low threshold mechanical stimulation of the urethra and anus, respectively. (4) The axons from the bladder, urethra and anus were presumably myelinated (conduction velocity above 2 m/s) and conducted at 10.3±6.1 m/s (n=34, mean±SD), 26.3±9.3 m/s (n=13) and 9.5±5.1 m/s (n=37), respectively. The axons from the colon conducted at about 0.5 to 16 m/s (n=20), 13 of them conducting at less than 2 m/s. About 75% of the axons which could not be activated by mechanical stimulation of the visceral organs were presumably unmyelinated (conduction velocity below 2 m/s). (5) Some ongoing activity was found in 9 out of 26 afferent units from the anus but, with one exception, the afferent units from the bladder, urethra and colon were silent. (6) It is concluded that the pelvic afferent units from the urinary bladder, urethra, colon and anus consist of distinct populations with characteristic response patterns. There is no indication from this investigation that the urinary bladder is supplied by sacral afferents which are only recruited at high intravesical pressures during passive distension and isovolumetric contractions and which are possibly associated with pain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00580280
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  • 27
    Electronic Resource
    Electronic Resource
    Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    Details
    ISSN: 1432-1912
    Keywords: Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The cardiac glyoosides digitoxin, ouabain, digoxin and peruvosid labelled with3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine. 2. Calculation of the amount of glycosides totally absorbed from the3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%. 3. The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood. 4. The amount of glycoside excreted in the bile is for peruvosid 15,5% of the amount absorbed, for ouabain 1,9%, for digoxin 1,4% and for digitoxin 0,8%. The3H-activity excreted in urine is very small and can be disregarded. 5. Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only 1/4. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01002379
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  • 28
    Electronic Resource
    Electronic Resource
    Über die Gefäßversorgung des Corpus callosum der Katze (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    Details
    ISSN: 1432-0568
    Keywords: Arterial supply ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 27 Katzen beiderlei Geschlechts wurde die Blutversorgung des Corpus callosum untersucht. Dabei wurden folgende Befunde erhoben: Der Balken der Katze wird im Bereich des Rostrum und Genu sowie im vorderen und mittleren Truncuabschnitt aus der Arteria cerebri anterior versorgt und zwar über Äste, die den Arteriae pericallosae und den Arteriae genu corporis callosi entstammen. Diese Äste wurden als Arteriae callosi superiores und inferiores bezeichnet. Lediglich im hinteren Truncusabschnitt und im Splenium erfolgt die Versorgung neben Ästen der A. pericall. auch über solche der Arteriae cerebri mediae und posteriores. Die Blutgefäße treten dolchartig in den Balken ein, teilen sich dann baumartig weiter auf und gehen in ein Capillarnetz über, das in Richtung des Nervenfaserverlaufes ausgezogen ist. Auf in der Literatur bereits bekannte, aber oft vernachlässigte Besonderheiten der Arteria carotis interna und des Circulus arteriosus wird hingewiesen.
    Notes: Summary In investigations on 27 cats of both sexes, the arterial supply of the corpus callosum was studied. The findings are as follows: In the region comprising rostrum and genu as well as in the fore and middle trunk sections, blood supplied by branches of the arteriae pericallosae and the arteriae genu corporis callosi which originate from the arteria cerebri anterior. These branches were designated arteriae callosi superiores and inferiores. However, in the posterior section of the trunk and in the splenium the blood is supplied by branches of the aa. pericall. and, in addition, by branches of the arteriae cerebri media and posteriores. The blood vessels penetrate the corpus callosum in bayonet fashion, then arborise and finally become a capillary network which is elongated in the direction of the course of the nerve fibres. Attention is drawn to peculiarities of the arteria carotis interna and the circle of Willis which, although known in the literature, are rarely referred to.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00522492
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  • 29
    Electronic Resource
    Electronic Resource
    Quantitative Untersuchungen an Gliazellen im Corpus callosum wachsender Katzen nach Perfusions- und Immersionsfixierung (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    Details
    ISSN: 1432-0568
    Keywords: Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Gehirne von Tieren aus 4 verschieden alten Würfen junger Katzen wurden teils lebensfrisch durch Perfusion, teils nach 24 Std durch Immersion fixiert und für Vergleichsuntersuchungen in Paraffin eingebettet. Bei Betrachtung der Gliazellen des Corpus callosum ergab sich: 1. Nach Perfusionsfixierung sind die Kerne der Gliazellen groß und elliptisch. Sie sind wasserklar und haben eine scharf gezeichnete Chromatinstruktur. Nach Immersionsfixierung 24 Std p.m. sind die Kerne dagegen klein und rund, homogen dunkel gefärbt und haben ein kaum zu erkennendes Chromatingerüst. 2. Nach Perfusionsfixierung sieht man im Balken der ganz jungen Tiere zahlreiche Mitosen. Sie fehlen bei den durch Immersion fixierten Geschwistertieren desselben Wurfes. 3. Die nach verschiedener Fixierung beobachteten Unterschiede in der Form der Gliazellkerne werden durch Messungen der Quer- und Längsachsen erfaßt.
    Notes: Summary In four litters of young cats, some of the brains were fixed by perfusion and the others by immersion. The material was embedded in paraffin and the neuroglia was investigated in sections through the corpus callosum. It was found that: 1. After fixation by perfusion the nuclei of the glia cells are large and elliptic. The caryoplasm is clear and there is a distinct structure of the chromatin. After fixation by immersion the nuclei of the same cells are small and round. The caryoplasm is dense and the structure of the chromatin is not clearly visible. 2. After fixation by perfusion mitotic figures are present. They are absent in the brains fixed by immersion. 3. Following different fixation, there are differences in the shape of the nuclei of the glial cells. These differences have been investigated in detail by measuring the diameters of the nuclei.
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    URL: http://dx.doi.org/10.1007/BF00521281
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    The lateral cervical nucleus in the cat IV. A light and electron microscopical study after midbrain lesions with demonstration of indirect wallerian degeneration at the ultra-structural level (1969)
    Springer
    Experimental brain research 7 (1969), S. 51-67 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lateral cervical nucleus (LCN) has been studied with the light and electron microscope after midbrain lesions in kittens of different ages, and in adult cats. It has been shown that nerve cells remain within the contralateral LCN after hemisection of the midbrain. performed on 1 day old kittens. The estimated number of these remaining cells was 3–19% in the different cases. No fibers descending to the LCN from levels rostral to the midbrain could be demonstrated in adult cats with the Nauta technique. A combined Nauta and electron microscopical investigation was performed on kittens operated on at different ages and allowed to survive varying times postoperatively. At the operations the LCN-axons were transected at midbrain level. The Nauta investigation demonstrated silver impregnation of degenerating LCN-neurons on the affected side of the same type as has been described recently in other neuronal systems following axonal transection. The ultrastructural study revealed electron dense degenerating dendrites and probably also nerve cells within the LCN. The dense degenerative changes were very similar to the dense degeneration in terminal boutons following transection of parent axons. The potential value of the findings for electron microscopical research in neuroanatomy is discussed. The results in terms of connections of the LCN are discussed in the light of known anatomical and physiological data of the LCN.
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    URL: http://dx.doi.org/10.1007/BF00236107
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    Integration konvergierender Afferenzen in der bulbären Formatio Reticularis der Katze (1969)
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    Details
    ISSN: 1432-1106
    Keywords: Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Ein konditionierender corticaler Reiz inhibiert den somatischen Startlereflex bei Katzen unter Chloralosenarkose für eine Dauer von mehr als 200 ms. Die Interaktionen zwischen beiden Reizen laufen in der bulbären und pontinen Formatio reticularis ab. 2. Dem Startlereflex liegt eine polysynaptische Erregungsschleife zugrunde, die die bulbäre und pontine Formatio reticularis durchzieht. Die Resistenz der reticulären Neurone gegenüber repetitiver Stimulation wurde als Kriterium ihrer funktionellen Lokalisation auf dem polysynaptischen Reflexbogen gewertet. 3. Die corticale Inhibition wird im Verlaufe der polysynaptischen Erregungsschleife zunehmend stärker. Neurone, die von den Startlereflexafferenzen direkt erregt werden, werden durch den corticalen Reiz nicht inhibiert. Dies schliebt eine präsynaptische Inhibition der reticulopetalen Fasersysteme aus.
    Notes: Summary 1. The startle reflex evoked by cutaneous stimulation in cats under chloralose anesthesia is inhibited for more than 200 ms by a conditioning cortical volley. The interaction between the cutaneous and the cortical volley takes place in the bulbar and pontine reticular formation. 2. The startle reflex involves a series of reticular neurones. Resistance to repetitive stimulation has been determined to evaluate the functional localization of each neurone within this polysynaptic path. 3. Inhibition following the cortical volley becomes increasingly more effective along the course of the polysynaptic path and is completed within 5–6 ms. Reticular neurones excited directly by the spino-reticular afferents are not inhibited, thus excluding a presynaptic inhibition of the spinoreticular fibres.
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    URL: http://dx.doi.org/10.1007/BF00235440
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    Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells (1969)
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    Details
    ISSN: 1432-1106
    Keywords: Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Examination of cutaneous receptive fields (RFs) of lamina 5 cells in the lumbar spinal cord of decerebrate cats shows them to have three distinct zones with respect to mechanical and electrical stimulation. The mean response rate to both mechanical and electrical stimulation in zone 1 increases steadily up to the highest strengths used; in zone 2, surrounding zone 1 mainly proximally, mild stimuli reduce the mean rate, stronger stimuli increase it; in zone 3, mainly proximal to zone 2, all stimuli reduce the rate. Temporally, zone 1, electric shocks near threshold produce bursts of firing followed by inhibition. With increased stimulus strength, the bursts lengthen to a second or more. In zones 2 and 3, inhibition at all strengths is preceded at higher strengths by bursts of firing. Cold-blocking the spinal cord at lower thoracic levels reversibly increases the ongoing activity of these cells, increases the area of zones 1 and 2, and almost completely suppresses all inhibition. Stimulation of dorsal columns and threshold stimulation of distant dorsal roots inhibits ongoing and induced activity. Barbiturate decreases ongoing activity and the duration of firing produced by cutaneous electrical stimulation but does not decrease inhibition. These results are consistent with a model in which low-threshold fibres are excitatory only over a small central area of the RF of a lamina 5 cell (zone 1), high threshold fibres are excitatory over a larger area (zones 1 and 2), and low threshold fibres are inhibitory over the entire receptive field (zones 1, 2 and 3) with a slower time-course. This inhibition is tonically enhanced by descending influences in the decerebrate cat. It is suggested that the high and low threshold fibres correspond approximately to the small and large diametre fibres whose balance is the basis for the coding of pain in the theory of melzack and wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235240
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    Die Bedeutung der Vorderhirnkommissuren für die Koordination bilateraler EEG-Muster (1969)
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spontaneous EEG-patterns and evoked potentials (EP's) of symmetrical cortical areas were recorded in chronic and acute cats before and after section of the corpus callosum, the commissura anterior and posterior and the massa intermedia. The spontaneous EEG was recorded without and with anesthesia, EP's after electrical stimulation of the fore-paws only during nembutal anesthesia. — No changes in the bilateral coordination of spontaneous and evoked EEG-patterns could be seen after commissurotomy (CT). The bilateral coherence of EEG-waves as revealed by cross-correlation is low already in the normal cats and does not change significantly after CT. The values of cross-correlation coefficients at T = ± 15 msec vary during one EEG-record between -0.25 and +0.25 in the somatosensory, suprasylvian and temporal areas (mean values slightly above 0). In the visual area occasionally positive values between 0.5 and 0.8 were seen, but also here a large variation was found in all animals and the mean values were below 0.1. No consistent phase shift between both sides was observed. EEG-patterns like spindles or arousal, still occurred together in both hemispheres after CT, the variability of their exact beginning or end was the same as in controls. Spontaneous spindles often lasted longer after section of the massa intermedia. Homolateral EP's in the somato-sensory area were still present after CT. Rhythmical afterdischarges could be restricted to the contralateral somato-sensory cortex even before CT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239029
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    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Keywords: Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
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    URL: http://dx.doi.org/10.1007/BF00235450
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    Pyramidal control of fusimotor neurons supplying extensor muscles in the cat's forelimb (1969)
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    Details
    ISSN: 1432-1106
    Keywords: Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of cortical stimulation upon dynamic and static sensitivities of the sensory endings in muscle spindles have been analyzed. 63 single afferent fibers from the muscle spindles of the forelimb extensors: M. flexor carpi radialis, M. flexor digitorum communis and M. palmaris longus were isolated in dorsal root filaments in 20 adult cats under chloralose-urethane anesthesia. They were identified by their response to stimulation of the median nerve. 1. Surface anodal repetitive stimulation of the anterior sigmoid gyrus was found to produce an enhancement of static response of single Group II fibers. Effective area was localized in a restricted region which corresponded to the forelimb motor area. The effect was obtained without any concomitant muscle contraction. Similarly, the stimulation increased the resting discharges of the Group Ia fibers from the same muscles. 2. Stimulation of the same area in the cerebral cortex was also found to increase the dynamic sensitivities of primary sensory endings. The increase was revealed by an enhancement of initial burst discharge during relaxation period of a twitch contraction caused by median nerve stimulation. 3. These results indicate that stimulation of the forelimb motor area has a facilitatory effect on both the static and dynamic fusimotor neurons innervating the muscle spindles of the test muscles. 4. The effects were reproduced in pyramidal tract preparations in which the brainstem was cut either at the level of the midbrain except for the cerebral peduncle or at the level of caudal medulla oblongata sparing the pyramid. 5. The threshold for the fusimotor effects was less than 1.3–1.5 times threshold of the pyramidal tract discharge, when the best spot for eliciting the fusimotor response was chosen. These results indicate that the effects of cortical stimulation are mainly mediated by the fast conducting pyramidal tract fibers.
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    URL: http://dx.doi.org/10.1007/BF00238324
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    Contrôle de l'activité des fibres fusimotrices dynamiques et statiques par la formation réticulée mésencéphalique chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of repetitive stimulation of the mesencephalic reticular formation (MRF) on the static discharge and dynamic sensitivity of muscle spindle primary endings (soleus muscle) were studied in cats anaesthetized with Halothane (Fluothane). By progressive increasing the depth of anaesthesia three different fusimotor effects could be observed: 1. A static effect; the static discharge of the primary endings was strongly increased; the response to phasic stretch was decreased or remained unaltered. 2. A dynamic effect; the dynamic sensitivity of the primary endings was powerfully increased while the rate of discharge under static conditions was only slightly augmented. 3. A depressant effect; the static discharge and the dynamic sensitivity of primary endings were decreased. Repeated stimulation elicited successive static and dynamic effects. No specific regions within the MRF could be related to a particular effect.
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    URL: http://dx.doi.org/10.1007/BF00235241
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    Etude fonctionnelle du contrôle de l'activité des fibres fusimotrices dynamiques et statiques par les formations réticulées mésencéphalique, pontique et bulbaire chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 325-345 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. During a progressive increase of Fluothane (Halothane) anaesthesia, repetitive stimulation of the mesencephalic retioular formation (MRF) produces several fusimotor effects — static, dynamic or depressant — on primary endings of soleus muscle spindles (Vedel et Mouillac-Baudevin 1969). 2. Transection of the brain immediately rostral to the site of stimulation may increase the dynamic effect but does not alter the static or the depressant effects. 3. A section of the rubrospinal tract does not modify the fusimotor effects elicited by stimulation of the MRF. 4. Transections of the spinal cord have shown that the pathways responsible for the transmission of these effects are mainly situated in the ipsilateral ventral and ventrolateral funiculi which contain the efferent fibers from the pontine reticular formation (PRF), from the bulbar reticular formation (BRF) and from the vestibular nucleus. 5. Contra and ipsilateral PRF stimulation produces the static fusimotor effect; contralateral stimulation from a small anterior region produces the dynamic effect. 6. Stimulation of the lateral part of the ipsilateral BRF elicits the dynamic effect while stimulation of the medial part elicits the static effect.
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    URL: http://dx.doi.org/10.1007/BF00235242
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    Die asynchrone und lokal umschriebene Reizwirkung von Mittelfrequenz-Dauerströmen im Hypothalamus der Katze (1969)
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. In order to compare the selective value of repetitive cathodal pulses of 8 c.p.s. and of continuous sine-wave alternating currents of 5000 c.p.s. (middle frequency current) when applied to brain tissue, explorations were made in the region of the hypothalamus that had yielded defence and/or flight reactions in earlier experiments. The region was explored by stimulating each point in turn with both current forms. At the same time measurement was made of the impedance of the brain tissue, and the effects produced by altering the time of rise of the middle frequency current on threshold of responses were also studied. The experiments were carried out on unanaesthetized, freely moving cats. 2. Both stimulation types produced affective (“emotional”) responses. The patterns elicited by low frequency cathodal pulse stimulation were often associated with stimulus-bound phasic muscle activity, i.e., flapping of ears, and twitching of whiskers, or, rotation of the head. Such extraneous motor effects were rarely obtained when continuous middle frequency currents were applied, and were tonic in character when present. 3. Mapping of reactive points revealed that the area producing defence or flight following middle frequency stimulation is smaller in size than the field delimited by means of repetitive cathodal pulse stimulation. These results strongly suggest that spread of current can be reduced by using middle frequency current stimulation. This apparently local (and hence highly selective) action is paralleled by a lower impedance of the brain tissue to the rapidly changing polarity of this current. 4. The hissing (and/or growling) associated with the defence pattern showed adaptation to suddenly rising middle frequency currents of 30 secs duration. An increase in threshold of hissing occurred when the time of rise of the current was prolonged. Flight, in contrast, was obtained at the same critical intensity regardless of the time of rise of current. 5. The nature of the stimulatory action of middle frequency current (examined in the peripheral nerve by Wyss) and the advantages presented by this new method of brain stimulation are briefly discussed.
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    URL: http://dx.doi.org/10.1007/BF00238329
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    The lateral cervical nucleus in the cat III. An electron microscopical study after transection of spinal afferents (1969)
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of terminal degeneration within the lateral cervical nucleus (LCN) after transection of its spinal afferent fibers 2 days–2 years earlier is described. The degeneration after 2 days was of both the neurofilamentous and dense type. The highest number of degenerating terminals, about 15%, was found after 4–5 days. Then most of the degenerating boutons were of the dense type. The degenerating terminals had synaptic contact with cell bodies and dendrites of LCN-neurons. Removal of the degenerating boutons seemed to be effected by a phagocytic cell present in increased number compared to the normal LCN. In cases with long survival times an increase in the number of astroglial filaments was observed. In an animal where the spinal afferents to the LCN had been cut 2 years earlier a decrease in medium size of the neurons was observed. The amount of dendritic spines was also considerably smaller than normally.
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    URL: http://dx.doi.org/10.1007/BF00236106
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    Inhibition in the medial geniculate body of the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    Details
    ISSN: 1432-1106
    Keywords: Medial geniculate body ; Inhibition ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Inhibitory activity in the cat medial geniculate body (MG) was examined by stimulating electrically and acoustically the input and output of the MG. 2. A longer and more profound depression of excitability occurs following a click-evoked potential in the MG than in the inferior colliculus (IC) in both anesthetized and unanesthetized states. Recovery is cyclic in the barbiturate MG preparation. 3. Electrical stimulation of the brachium of the inferior colliculus (BIG) evokes a field potential in the MG consisting of clearly distinguishable presynaptic and postsynaptic components. The presynaptic component recovers rapidly, while the postsynaptic component requires 100–200 msec for full recovery. This depression of excitability is localized within the MG since cortical ablation does not alter its occurrence. 4. Stimulation of the BIC mimics the effects of click stimulation on single units. Excitatory, inhibitory and reverberatory responses are evoked by the BIC shock. Suppression of single unit activity correlates with the depression of excitability following a BIC-evoked field response. 5. Cortical stimulation can evoke antidromic and trans-synaptic unit responses in the MG, as well as causing a variety of inhibitory effects and reverberation. In view of the fact that cortical ablation does not impair the recording of these responses to afferent stimuli, it is suggested that the cortical-evoked responses are at least partly mediated by antidromic conduction to MG. 6. Evidence is presented that inhibitory effects of both afferent and cortical stimulation are due to active inhibition of MG unit activity. Speculations are made as to the mechanisms producing inhibition and reverberation in the MG.
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    URL: http://dx.doi.org/10.1007/BF00236108
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    Electronmicroscopic observations on the structure of the pontine nuclei and the mode of termination of the corticopontine fibres an experimental study in the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 95-110 
    Details
    ISSN: 1432-1106
    Keywords: Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electron microscopical changes occurring in the pontine nuclei following unilateral lesions of the primary sensorimotor cortex have been studied in 7 cats with a survival time from 2–23 days. A description is also given of the fine structure of the pontine regions in receipt of the fibres. These regions are shown in Fig. 1. The study shows that the boutons are practically only in synaptic contact with dendrites. The bouton density on these is only 16%. The boutons are of the en passage and terminal type, with the latter as the most common (Figs. 4a-e). The synaptic vesicles are rounded or elongated. The formaldehyde fixed material had 17.8% boutons with vesicles of the elongated type; the material fixed with a mixture of formaldehyde and glutaraldehyde had only 11.5% of such boutons. The degenerating boutons show the dark type of reaction and the majority of the corticopontine fibres are of the type shown in Figs. 4d and 4e. Astrocytes and microglial cells participate in the removal of degenerating boutons and terminal fibres. Degenerating boutons are present even at the 23 day stage and some have apparently only started to degenerate.
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    URL: http://dx.doi.org/10.1007/BF00235436
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    Eine faktorenanalyse von schwellen subcorticaler reizantworten (1969)
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    Details
    ISSN: 1432-1106
    Keywords: Evoked potential thresholds ; Factor analysis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zur Beschreibung von Korrelationen zwischen zahlreichen elektrophysiologischen Daten aus verschiedenen Hirngebieten wurde eine Faktorenanalyse nach der Hauptachsenmethode gerechnet. Ausgangsmaterial dieser Analyse waren Schwellen subcortical ausgelöster und abgeleiteter Antwortpotentiale auf Einzelreize. Das resultierende Faktorenmuster ermöglicht ein quantitatives Konzept der Schwellendetermination subcorticaler Reizantworten und zugleich ein Modell von Funktionsbeziehungen zwischen einigen Hirnstrukturen. Die Reizungen und Ableitungen erfolgten bei 35 encéphale isolé-Katzen mit Hilfe bipolarer Elektroden in folgenden Arealen: Amygdala, Hippocampus, Septum, N. dorsomedialis Thalami, Hypothalamus posterior und Formatio reticularis mesencephali. Es wurden 435 Korrelationskoeffizienten zwischen den Schwellen von 30 subcorticalen Verbindungen gebildet und zum Zwecke einer Datenreduktion durch eine Matrix von 5 Faktoren reproduziert. 1. Jeder Faktor repräsentierte hohe Schwellenkorrelationen zwischen den efferenten Projektionen jeweils eines Kerngebietes. Demnach nimmt im allgemeinen die Aktivität des Reizortes den größten Einfluß auf die Schwelle eines Antwortpotentials. Diese Hypothese ist durch pharmakologische Untersuchungen belegt worden [27] 2. Kovariationen von Reizantworten mit identischen Ableiteorten ergaben sich ausnahmslos, wenn die Latenzzeiten mehr als 11 msec betrugen. 3. Zusätzlich zeigte die Faktorenmatrix Schwellenkorrelationen zwischen: a) den hypothalamischen Efferenzen und mehreren hippokampalen Afferenzen langer Latenz (positive Korrelationen) b) retikulo-limbischen Verbindungen und „primären” Efferenzen von Amygdala und Hippocampus (positive Korrelationen) c) Antwortpotentialen, die durch Reizung der Formatio reticularis, und solchen, die durch Reizung des N. Amygdalae ausgelöst waren (negative Korrelationen) d) den Efferenzen des N. dorsomedialis Thalami und limbischen Projektionen langer Latenz zur mesencephalen Formatio reticularis (positive Korrelationen) Die Interpretation dieser Zusammenhänge bestätigt und erweitert einige bekannte Modelle von Beziehungen zwischen subcorticalen Kerngebieten. Abschließend wird mit Rücksicht auf die Linearität der mathematischen Methode die Anwendbarkeit der Faktorenanalyse auf Schwellen von Reizantworten diskutiert.
    Notes: Summary In 35 cats (encéphale isolé) evoked responses were elicited and recorded with bipolar electrodes from the amygdala, hippocampus, septum, dorsomedial thalamic nucleus, posterior hypothalamus, and mesencephalic reticular formation. Correlations between the thresholds of responses in different areas following stimulation of other areas were described by a factor analysis according to the principal axis method. 435 coefficients of correlation were calculated and reproduced by a matrix of 5 factors for the purpose of data reduction. Each factor represented high threshold correlations between the efferent projections of one region, which suggests that the activity of the stimulated site exerts a major influence on the evoked potential threshold. This is supported by pharmacological studies [27, 49]. Covariations of responses recorded in the same nucleus were always found, if the latencies exceeded 11 msec. The factor matrix indicated threshold correlations between: the efferent projections of the hypothalamus and several long latency afferent projections to the hippocampus (positive correlations); reticulo-limbic connections and “primary” efferent connections of the amygdala and hippocampus (positive correlations); evoked potentials following reticular and amygdaloid stimulation (negative correlations); the efferent projections of the dorsomedial thalamic nucleus and long latency limbic projections to the mesencephalic reticular formation (positive correlations). The interpretation of these relationships confirms and extends some well known models of relations between subcortical regions. The applicability of factor analysis to evoked potential thresholds is discussed with regard to the linearity of the mathematical method.
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    URL: http://dx.doi.org/10.1007/BF00234927
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    Interaction of defence and flight reactions produced by simultaneous stimulation at two points in the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 130-149 
    Details
    ISSN: 1432-1106
    Keywords: Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The results presented in the present paper are an extension of preceding work devoted to exploration of the hypothalamic defence and flight fields using coaxial electrodes with small cathode. In 33 cats simultaneous stimulation was applied to two points which upon single stimulation had yielded defence, flight, or defence and flight respectively. Results were compared with those produced at either point alone. In 2 cats combined stimulation of a defence and a flight point was carried out with a stuffed cat present. 2. The latencies and rates of the vocal effects associated with defence (growling and hissing), and the latencies of flight (jump from the table) were measured. 3. Simultaneous stimulation of two points which had yielded defence, or of two points which had yielded flight resulted in facilitation (spatial summation) of the effects evoked: a more complete defence response associated with decrease of the latencies and increase in the rates of the vocal effects; decrease of flight latencies and increase of flight impetuosity. 4. Simultaneous stimulation of a defence point which had yielded growling at lower threshold than hissing, and of a point which had yielded flight resulted in facilitation of hissing. Growling and flight were often suppressed; when they occurred, latencies were lengthened and growling rates were increased somewhat. 5. Stimulation of a defence point with a dummy present produces striking (fending off). Simultaneous stimulation of a flight point resulted in facilitation of both hissing and striking. 6. It is concluded that the complex patterns obtained when defence is combined with flight are the result of facilitatory and inhibitory interaction between the elements of the individual patterns.
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    Electronic Resource
    Räumliche summation und hemmungsvorgänge im receptiven feldzentrum von retina-neuronen der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    Details
    ISSN: 1432-1106
    Keywords: Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. An retinalen Ganglienzellen der Katze wurde die räumliche Summation im receptiven Feldzentrum (KFZ) bei Dunkeladaptation und Helladaptation durch mittelpunktzentrierte Lichtreize verschiedener Flächengrößen untersucht. Als Kriterium dienten die Entladungsraten der ersten 200 und 500 msec nach Licht-an oder Licht-aus. Das Summationsverhalten wurde sowohl für Einzelneurone als auch gruppenstatistisch für die beiden Neuronen-Systeme B (on-Zentrum) und D (off-Zentrum) untersucht. 2. Die räumliche Summation ist auf den inneren Bereich des RFZ beschränkt: bei on-Zentrum-Neuronen steigt die Entladungsrate nur bis zu Reizflächen, die etwa 1/5 der Fläche des RFZ belichten, bei off-Zentrum-Neuronen bis zu Reizflachen von ca. 1/10 des RFZ. Bei Variation der Reizfläche zwischen 20 und 100% der Fläche des RFZ bleibt das Entladungsniveau konstant (asymptotischer Verlauf der Summationskurve). 3. Die Begrenzung der räumlichen Summation auf einen kleinen Bereich des RFZ beweist eine bereits im Feldzentrum wirksame Hemmung. Diese Zentrum-Inhibition begrenzt die Erregungssummation im RFZ bei zunehmender Flächengröße des Lichtreizes. 4. On- und off-Zentrum-Neurone unterscheiden sich in beiden Adaptationszuständen in der Höhe des Entladungsniveaus. Die Entladungsraten der on-Zentrum-Neurone nach Licht-an übertreffen um ein Mehrfaches die Entladungsraten der off-Zentrum-Neurone nach Licht-aus. Die Unterschiede sind gruppenstatistisch hoch signifikant. Die interneuronale Variabilität der Entladungsraten ist bei den onZentrum Neuronen erheblich geringer als bei den off-Zentrum-Neuronen. 5. Dunkel -und Helladaptation führt zu signifikantem Unterschied der Entladungsraten: bei Helladaptation liegt die Impulsrate beider Neuronentypen höher als bei Dunkeladaptation und der Summationsbereich ist um 5–10% größer. 6. Für die mathematische Beschreibung der Summationsverläufe ist die Hyperbel besser geeignet als die logarithmische und Potenzfunktion. Logarithmus- und Potenzfunktionen beschreiben den konstanten asymptotischen Teil der Summationskurven ungenügend und eigenen sich nur für den Kurventeil im innersten Summationsbereich. Die Bedeutung der Befunde für eine dynamische Interpretation der visuellen Feldorganisation und mögliche Beziehungen zur lateralen Umfeldhemmung werden diskutiert.
    Notes: Summary 1. Spatial summation of suprathreshold light stimuli within receptive field centers (RFZ) of retinal ganglion cells was investigated during dark and light adaptation in cats. The mean discharge rates for 200 and 500 msec following light on or off were the computed response criteria. The summation effects were analyzed for single neurones and statistically for grouped neuron populations of the two neuronal subsystems B (on-center-neurones) and D (off-center-neurones). 2. Spatial summation is restricted to a small part of the RFZ. On-centerneurones increase their on-discharge rates with increasing spot sizes, only if the stimulus illuminates less than 1/5 of the RFZ. The summating area of the off-centerneurones is smaller (about 1/10 of the RFZ). 3. The limitation of spatial summation to a small part of the RFZ indicates the existance of inhibition within the RFZ. This center-inhibition sets a constant limit for excitation summation in the RFZ. 4. The mean neuronal response rates for the 2 subsystems show significant differences: The on-discharges of the on-center-neurones exceed the off-discharges of the off-center-neurones by a factor of 3–5. These highly significant differences occur at both adaptation levels and are not due to different spontaneous activity. Interneuronal response variability of the off-center-neurones was twice as large as that of the on-center-neurones. 5. Change from dark to light adaptation had only a small but significant influence on summation properties. The poststimulus discharge rates were higher during light adaptation and the summating area was slightly larger (about 5–10%). 6. A comparative curve fitting procedure for three suitable mathematical functions revealed that the hyperbola describes the neuronal summation curves better than a logarithmic or power function. The latter do not fit the constant asymptotic part of the curve. The significance of the results for a dynamic interpretation of the organisation of visual receptive fields is discussed.
    Type of Medium: Electronic Resource
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    Electronic Resource
    Räumliche summation im receptiven feldzentrum von neuronen des geniculatum laterale der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die räumliche Summation im receptiven Feldzentrum von Neuronen des Corpus geniculatum laterale (CG-L) wird beschrieben und mit entsprechenden Untersuchungen an retinalen Ganglienzellen verglichen. Neben größerer interneuronaler Variabilität ergeben sich ausgeprägtere Unterschiede der Summationseigenschaften der on-und off-Zentrum-Neurone. Der effektive Summationsbereich von etwa 1/5 der Fläche des RFZ ist in Retina und CGL etwa gleich. 2. Die on-Zentrum-Neurone des CGL zeigen in beiden Adaptationszuständen einen ähnlichen Summationsverlauf wie in der Retina. Das Entladungsnieau ist im CGL jedoch erheblich geringer und nicht durch Unterschiede in der Spontanaktivität zu erklären. 3. Die Mehrzahl der off-Zentrum-Neurone des CGL zeigt bei DA inverse Summationsverläufe wie in der Retina: durchgehende Verminderung der Entladungsrate der off-Antworten bei Vergrößerung der Reizfläche im RFZ. Eine kleine Gruppe zeigt einen parabelförmigen Summationsverlauf mit Entladungszunahme bis zu Reizflächen von 10–30% der Fläche des RFZ und darauffolgender Entladungsminderung. Bei Helladaptation zeigen fast alle off-Zentrum-Neurone diesen Parabelverlauf. Das durchschnittliche Entladungsniveau ist von dem retinaler offZentrum-Neurone nicht signifikant verschieden. 4. Die interneuronale Variabilität der Summationsvorgänge im RFZ von CGLNeuronen ist gegenüber den retinalen Ganglienzellen deutlich größer. Dies gilt insbesondere für die off-Zentrum-Neurone. Das Summationsverhalten von CGLNeuronen läßt sich daher nicht wie in der Retina durch einen Funktionstyp beschreiben. 5. Die Befunde sprechen für eine Transformation des retinalen Eingangs der off-Zentrum-Neurone im CGL, während die on-Zentrum-Neurone außer der bekannten Frequenzuntersetzung keine wesentliche Umformung erkennen lassen.
    Notes: Summary 1. Spatial summation in the receptive field center of neurones of the lateral geniculate body (CGL) is limited by inhibition to a small part of field center. Variations of stimulus size are only effective if the stimulus is smaller than about 1/5 of the area of receptive field center. Thus, the active summating area of the field center in the CGL corresponds to that of the retina. Geniculate neurones, however, show less homogeneous responses and the summation properties of the two neuronal subsystems (on-center-and off-center-cells), show greater differences than in the retina. 2. The form of summation curves for the on-center-neurones of the CGL is similar to those of the retina at both adaptation levels. However, the average responses rates in the CGL are considerably lower. This is not due to differences of spontaneous activity. 3. The summation characteristics of off-responses of off-center-neurones of the CGL are quite different from those in the retina. In dark adaptation the majority of CGL neurones respond with decreasing discharge rates to increasing spot-sizes within the field center. A small number show an initial increase of discharge rates up to stimulus sizes of about 1/10 of the receptive field center before a decrease occurs. This parabolic summation type is typical for most off-center-neurones in light adaptation. The mean discharge levels are the same as those of the retinal offcenter-neurones. 4. The higher interneuronal variability of summation curves especially of the off-center-neurones of the CGL indicates a more complex determination of the discharge properties of CGL neurones. This functional differentiation of single neurones is congruent with the more complex structural and synaptic organisation in CGL. 5. With respect to spatial summation, the results indicate a transformation of the retinal input of the off-center-neurones at the geniculate level, whereas the oncenter-neurones are nearly unchanged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234925
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    Electronic Resource
    Langfristige Verträglichkeitsprüfung mit Benperidol an der Katze (1969)
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    Details
    ISSN: 1432-2072
    Keywords: Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Daily doses of 1–10 mg Benperidol were given perorally to cats during 26 months. The general behaviour and the EEG were unchanged during the treatment, in particular no signs of dyskinesia were observed. After discontinuation of the administration, the behaviour and the EEG of the animals stayed normal. Thus no lasting and irreversible side effects could be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403690
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  • 47
    Electronic Resource
    Electronic Resource
    Effects of LSD on the spontaneous and evoked activity of retinal and geniculate ganglion cells (1969)
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    Details
    ISSN: 1432-2072
    Keywords: LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of LSD 25 (i. v. injection) on the spontaneous and evoked activity of the visual system was investigated in cats. 50 γ/kg did not change significantly the ERG and the visual cortical evoked potential. The spontaneous discharge rate of 14 out of 21 retinal ganglion cells showed an increase which reached its maximum within 20–30 min and which could still be present 1 hour following the injection. One third of the retinal units showed a slight depression of their spontaneous dischaRge rate with about the same time course. Single units of the LGN showed about the same behaviour. The response to light stimulation was slightly increased in some units and light induced inhibition was slightly shortened. The possible mechanism of the LSD-effect on retinal ganglion cell activity is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403713
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  • 48
    Electronic Resource
    Electronic Resource
    Responses of neurones in cat's abducens nuclei to horizontal angular acceleration (1969)
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    Details
    ISSN: 1432-2013
    Keywords: Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single cell activity was recorded extracellularly from neurones in cat's abducens nuclei in unanesthetized, decerebrate preparations. Two types of neurones were found. i) The motoneurones (type IIA) increased their firing linearly or exponentially to contralateral constant angular accelerations and decreased firing to ipsilateral rotation. The increased frequency was maintained at a constant level without any sign of adaptation. This constant level of maximum frequency was proportional to the logarithm of the acceleration applied. No significant differences of the frequency responses of tonic and silent motoneurones were found. The conduction velocities of the axons of spontaneously firing type IIA cells were slower than in silent neurones. Electrical stimulation of the contralateral VIIIth nerve led to activation of the type IIA cells; stimulation of the ipsilateral nerve resulted in inhibition of both spontaneous discharge and antidromic invasion of the motoneurones. ii) The type IA units increased their firing rate to ipsilateral rotation and ceased to discharge in response to contralateral rotation. They never were excited antidromically by stimulation of the VIth nerve. However, they were excited by stimulation of the ipsilateral VIIIth nerve. Their possible functional role in the vestibulo-ocular system was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587754
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  • 49
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    Electronic Resource
    Die Rolle „spezifischer” und unspezifischer Afferenzen für den Antrieb der Atmung, untersucht durch Reizung und Blockade von Afferenzen an der decerebrierten Katze (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 189-205 
    Details
    ISSN: 1432-2013
    Keywords: Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 11 intercolliculär decerebrierten Katzen wurde geziegt, daß Kälteblockade eines eng umschriebenen Feldes auf der ventralen Oberfläche der Medulla oblongata, wie früher für anaesthesierte Tiere beschrieben, zu Atemstillstand führt, wenn die kontralaterale Stelle auf der Medulla oblongata, die Sinusnerven und die Vagi ausgeschaltet sind. Zu Atemstillstand kam es auch, wenn statt der Kälteblockade 2% Novocain durch lokale Superfusion bei gleichzeitiger Gegenspülung der Umgebung mit künstlichem Liquor angewandt wurde, oder wenn ein mit 1% Novocain getränkter Tupfer lokal aufgelegt wurde. Außerdem führte Kälteblockade zu Atemstillstand, wenn durch kontinuierliche auch während der Kälteblockade anhaltende elektrische Reizung eines N. femoralis oder hinterer Lumbalwurzeln an decerebrierten Katzen oder des Hypothalamus an einer anaesthesierten Katze Steigerungen der Ventilation ausgelöst worden waren. Elektrische Reizung eines Sinusnerven führte zu Atemsteigerungen. Bei Sinusnervenreizung während eines durch Kälteblockade ausgelösten Atemstillstands kam es zu rhythmischer Atmung. Aus diesen Untersuchungen wird geschlossen, daß mit der Ausschaltung der beschriebenen Felder auf der ventralen Oberfläche der Medulla oblongata am sonst desafferentierten Tier die Gesamtheit der für die zentrale CO2-Empfindlichkeit verantwortlichen Strukturen erfaßt ist, daß nach Ausschaltung der zentralen und der peripheren Chemosensibilität eine unspezifische Aktivierung der Atmungszentren unwirksam ist und daß die Atmungszentren zur Ausbildung einer rhythmischen Atmung von spezifischen Antrieben abhängig sind.
    Notes: Summary It was shown in 11 decerebrated cats, that cooling of a small and well defined area on the ventral surface of the medulla will cause respiratory arrest if the contralateral area of the medulla, the vagi and sinus nerves are eliminated. This confirms earlier observations obtained in anesthetized cats. Apnea was also produced by local superfusion of 2% procain with simultaneous flushing of the immediate surrounding area with mock spinal fluid. Local application of a small sponge soaked with 1% procain had the same effect. Electrical stimulation of femoral nerves or posterior roots which results in hyperventilation on the decerebrated cat failed to show any effect during periods of cold blockade. There was no respiratory response to direct stimulation of the hypothalamus in an anesthetized cat during cooling. Electrical stimulation of one sinus nerve caused an increase of ventilation. Sinus nerve stimulation during apnea induced by cold blockade resulted in rhythmical respiration. It is concluded from these experiments: Blocking of the area under discussion on the ventral surface of the medulla, inhibits all structures responsible for the central CO2-sensitivity in the deafferentiated animal. There was no response to non-specific stimuli of the respiratory center after elimination of central and peripheral chemosensitivity. The respiratory centers apparently depend on specific stimuli to support rhythmical respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586928
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  • 50
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    Electronic Resource
    Defence, attack, and flight elicited by electrical stimulation of the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Affective behaviour patterns produced by electrical stimulation of the hypothalamus were studied in unanaesthetized, freely-moving cats. Bipolar stimulation with coaxial electrodes and small cathode was used to elicit defence, attack or flight. The development of these responses was studied by varying stimulation strength. In some experiments a stuffed animal was introduced in order to study the reactions of the cat to changes in the environment during stimulation. 2. The following responses were evoked at threshold intensity: (i) growling reaction; (ii) hissing reaction; (iii) two types of flight — type a preceded by hastily looking to and fro as if in search of an exit, type b preceded by inspection of surroundings, in most cases associated with sniffing. 3. Increasing stimulation 1.5 times threshold often yielded combined patterns. At points yielding the growling reaction a defence response in which growls alternated with hisses was obtained. The points yielding flight type a sometimes yielded hissing followed by flight. Increasing stimulation at hissing points yielded either a defence reaction or the combined effect hissing-flight. 4. The growling reactions were obtained from the tuber region. The hissing responses were obtained from points above the tuber. The flight reactions, type a, were produced from the intermediate zone extending from the level of the preoptic area to the mamillary bodies and type b from the caudo-lateral hypothalamus. 5. The reactions of the cats to a dummy during stimulation varied depending on the type of response which had been evoked in the absence of the dummy. The defence reaction was converted into threatening and striking of the dummy, the combined effects into threatening, striking or biting, culminating in sudden flight. The dummy was ignored during stimulation of points yielding flight type a, but examined by sniffing during stimulation of points yielding flight type b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234534
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    Electronic Resource
    Evidence for mediated transport of chloride in cat cerebral cortex in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The kinetics of the uptake of chloride by slices of cat cerebral cortex incubated in vitro have been studied for a wide range of concentrations of chloride and potassium in the incubation media. 1. In studies with 36Cl at a constant concentration of external K+, the rate of entry of chloride into slices of cat cerebral cortex (after equilibration with the fluid of the extracellular space) followed Michaelis-Menten kinetics with Vmax=7.7 μmoles/g/min and Km=245 mM. The kinetic data so described differ significantly from a curve describing simple diffusion (P 〈 0.02). 2. A clear dependence on concentration of K+ in the incubation medium was demonstrated. When external chloride was held constant at 6.8 mM and concentrations of potassium were varied over a range of 27–100 mM, the apparent rate of entry of chloride followed Michaelis-Menten kinetics with Vmax=0.191 μmoles/ g/min and Km=30.3 mM. 3. Under similar equilibrium conditions, the rate of influx of chloride was not statistically different from the rate of efflux, and the value for extracellular space (355 μl/g) derived by extrapolation from efflux data was of an identical order of magnitude to the value (352 μl/g) obtained from influx data. These values are essentially identical to those previously determined for chloride space of cat cerebral cortex in vivo (Bourke, Greenberg and Tower 1965). 4. The total, membrane-delimited content of chloride in cerebral cortex, as defined in these studies in vitro, was a function of the concentration of K+ in the incubation medium.
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    URL: http://dx.doi.org/10.1007/BF00234250
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  • 52
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    Electronic Resource
    Studies of the development and subsequent reduction of swelling of mammalian cerebral cortex under isosmotic conditions in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ionic parameters of incubation media which foster both the development and subsequent reduction of swelling of slices of cerebral cortex under isosmotic conditions of incubation in vitro are described. A linear relationship between increasing chloride concentrations in incubation media and progressive swelling of tissue slices (under conditions of constant temperature and K+ concentrations and isotonicity of incubation media) is demonstrated. Subsequent reduction of chloride concentration in incubation media together with reciprocal replacement by isethionate is associated with significant and characteristic reduction in the volume of tissue swelling when all other conditions of incubation, including isotonicity of the media, are kept constant. The ionic composition of the fluid of swelling under different conditions of incubation is derived together with the ionic composition and expected transmembrane potentials of the neuronal compartment of cerebral cortex in vitro. Mechanisms involved in the development and subsequent reduction of swelling of cerebral cortex in vitro are discussed, and proposals for possible clinical applications are suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234251
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  • 53
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    Electronic Resource
    Verbesserung der Resorption von Helveticosid und Helveticosol durch Substitution der Hydroxylwasserstoffe an der Digitoxose (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    Details
    ISSN: 1432-1912
    Keywords: Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Wirksamkeit verschiedener Ester und Äther von Helveticosid und Helveticosol bei i.v. und intraduodenaler Zufuhr an Katzen und Meerschweinchen geprüft. 1. Bei i.v. Dauerinfusion waren Helveticosol und seine Derivate bei Meerschweinchen etwa doppelt so wirksam wie die analogen Helveticosidverbindungen. Bei der Katze bestand kein Unterschied. Die Monomethyläther Cymarin und Cymarol waren gleich oder sogar stärker wirksam, alle übrigen Derivate deutlich schwächer als die Ausgangssubstanzen. 2. Die tödlichen Dosen bei intraduodenaler Injektion lagen beim Meerschweinchen für einige Substanzen in gleicher Größenordnung oder niedriger als die Titer bei i.v. Infusion. Diese hohe enterale Wirksamkeit kann bei Helveticosid und seinen Derivaten durch eine Reduktion zu dem wirksameren Helveticosol, bei Estern außerdem durch eine Hydrolyse zu wirksameren Glykosiden vorgetäuscht werden. 3. Bei intraduodenaler Infusion an Katzen waren alle geprüften Ester und Äther wirksamer als Helveticosid und Helveticosol. Die aus dem Verhältnis der toxischen Dosen bei i.v. und intraduodenaler Infusion berechnete enterale Wirksamkeit lag zwischen 20 und 50%. 4. Unterschiede in der Dauer der intraduodenalen Infusion bei Katzen lassen sich berücksichtigen, wenn man von der theoretischen Annahme einer exponentiellen und vollständigen Resorption ausgeht und die Halbwertszeit für die Resorption berechnet. Die minimale Resorptionsgeschwindigkeit lag bei einigen Derivaten in gleicher Größenordnung wie bei Digoxin und Digitoxin. Es wird auf den Unterschied zwischen der auf Grund der pharmakologischen Wirkung bestimmten relativen enteralen Wirksamkeit und der Resorptionsquote hingewiesen. Letztere ist für die Verläßlichkeit der therapeutischen Wirkung eines Glykosids bei oraler Gabe maßgebend.
    Notes: Summary The efficacy of several esters and ethers of Helveticosid and Helveticosol was assayed by intravenous and intraduodenal administration to cats and guinea-pigs. 1. In guinea-pigs, Helveticosol and its derivatives were approximately twice as active on intravenous infusion as the analogous derivatives of Helveticosid; in cats there was no significant difference. The monomethylethers Cymarin and Cymarol were equally or slightly more potent, all other derivatives were weaker than the original compound. 2. In guinea-pigs the lethal doses of some compounds on intraduodenal injection were equal to or even lower than those on intravenous infusion. This may partly be accounted for by a reduction of Helveticosid and its derivatives to the more potent Helveticosol analogues, partly by a hydrolysis of the esters, yielding compounds of higher activity. 3. On intraduodenal infusion in cats, all the investigated esters and ethers were more active than Helveticosid and Helveticosol. The relative enteral activity calculated from the ratio of the toxic doses on intravenous and intraduodenal infusion varied between 20 and 50%. 4. Due to a delayed absorption from the gastrointestinal tract, the toxic dose falls with a reduced speed of intraduodenal infusion. Assuming an exponential and complete absorption, the half time of absorption was calculated. For some of the compounds investigated, the speed of absorption was comparable to that of Digoxin and Digitoxin. The difference between the relative enteral activities determined by comparing equiactive doses on enteral and parenteral administration and the percentages of the glycosides which are absorbed from the gastrointestinal tract is pointed out. The latter is of prime importance for obtaining reproducible effects after enteral administration.
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    URL: http://dx.doi.org/10.1007/BF00536819
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    Electronic Resource
    Morphologische Untersuchungen an der Glandula bulbourethralis der Katze (1969)
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    Details
    ISSN: 1432-0878
    Keywords: Glandula bulbourethralis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Parenchym der Glandula bulbourethralis der Katze besteht aus weitlumigen, gebuchteten intraglandulären Gängen, in welche kurze, englumige, zumeist unverzweigte Tubuli einmünden. Der Drüse fehlt eine äußere Organkapsel, so daß ihre peripheren Tubuli stellenweise direkt zwischen den Fasern des quergestreiften M. bulboglandularis liegen. Die Drüsentubuli und die Buchten der intraglandulären Gänge sind mit einem einschichtigen Zylinderepithel ausgekleidet, auf den Gangfalten ist das Epithel abschnittsweise mehrreihig, Die sezernierende Epitheloberfläche ist durch die Ausbildung von interzellulären Sekretkapillaren vergrößert. Breite Zwischenzellspalten (Durchmesser etwa 1,5μ), in welche schlanke interdigitierende Cytoplasmafortsätze hineinragen, erstrecken sich von der Basalmembran bis kurz unter das Tubulusbzw. Ganglumen. Die lumenseitigen Zellgrenzen tragen einige stummelförmige Mikrovilli und besitzen zerklüftete Außenkonturen, die durch glykogenreiche Cytoplasmaprojektionen bedingt sind. Alle Epithelzellen sind reich an Mitochondrien. Die supranuklearen Abschnitte der meisten Gang- und Tubuluszellen enthalten Sekretgranula, welche im Elektronenmikroskop unterschiedliche optische Dichten aufweisen können. Die Granula enthalten ein PAS-positives, neuraminsäurehaltiges epitheliales Muzin, das in einzelnen Sekretkörnchen auch eine histochemische Reaktion auf Sulfatgruppen gibt. Alle Epithelzellen reagieren sehr stark auf unspezifische Esterase und stark auf β-D-Glucuronidase, β-D-Glactosidase sowie die Enzyme des Citronensäurezyklus, der Glykolyse und der Atmungskette (NAD-ICDH, SDH, ALD, LDH, ADH, GDH, NADH-T-Red, Cyt-Ox).
    Notes: Summary The bulbourethral glands of sexually mature male cats are studied with the light and electron microscope. The parenchyma consists of spacious, sinus-like intraglandular ducts and short, narrow, mostly unbranched tubular endpieces. The gland has no complete connective tissue capsule, consequently some of the peripheral tubules are situated directly in between the fibers of the surrounding bulboglandularis muscle. The endpieces and the sinus of the intraglandular ducts are lined by a simple columnar epithelium, whereas the folds of the ducts are generally covered by a low pseudostratified epithelium. The secretory surface of the cells is increased by intercellular canaliculi which communicate with the gland lumen. These canaliculi are identified on the light microscopic level by their strong 5′-nucleotidase activity. Furthermore widened intercellular spaces (approximately 1,5 μ in diameter) filled with slender, interdigitating cytoplasmic processes extend from the basal lamina to the apical junctional complexes. The luminal cell pole exhibits some short microvilli and forms irregularly shaped, glycogen containing protrusions. Within the cytoplasm of the gland cells numerous spherical mitochondria, some dense bodies, a typical Golgi apparatus, free ribosomes and a poorly developed endoplasmic reticulum are to be observed. Secretory granules which can be grouped into three types on the basis of their electron density occur in the supranuclear regions of most of the cells. According to histochemical tests all granules contain a periodate reactive sialomucin and some of them also sulfate groups. The glandular parenchyma is site of an exceptionally strong unspecific esterase activity and is rich in β-D-glucuronidase, β-D-glactosidase, aldolase, α-glycerophosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and cytochrome oxydase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335273
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    Mode of activation of hippocampal pyramidal cells by excitatory synapses on dendrites (1966)
    Springer
    Experimental brain research 2 (1966), S. 247-260 
    Details
    ISSN: 1432-1106
    Keywords: Synaptic excitation ; Hippocampus ; Pyramidal cells ; Dendritic activation ; Cat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following selective activation of four afferent paths that terminate exclusively on dendrites, only a small proportion of pyramidal cells in the hippocampal fields CA1 and CA3 discharged impulses. Following a single afferent volley, an EPSP was never observed even in cells synaptically excited. On tetanic stimulation (about 10/sec), a large EPSP developed, but this was not a prerequisite for an action potential. Studies of the extracellular field potentials corresponding to the EPSP and the population spike potential, indicated that the EPSP was generated across the dendritic membrane and that the spike was initiated in the neighbouring part of the dendritic tree, propagating from there along the thicker dendrites towards the soma. This conduction had an average velocity of 0.4m/sec, and, presumably, a relatively low safety factor. In certain cases, the intrasomatic electrode recorded small all-or-nothing spikes which presumably were generated in the dendritic tree. These small spikes (D-spikes) invaded the soma only if assisted by some additional depolarization, for example by frequency potentiation of excitatory synapses. The results indicate two functional types of pyramidal dendrites, the conducting and the synaptic type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236716
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  • 56
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    The inhibitory interneurones within the cerebellar cortex (1966)
    Springer
    Experimental brain research 1 (1966), S. 1-16 
    Details
    ISSN: 1432-1106
    Keywords: Inhibitory interneurones ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Extracellular microelectrode recording has been employed to study the responses of three types of interneurones in the cat cerebellar cortex: basket cells, superficial stellate cells and Golgi cells. The large unitary spike potentials of single cells were sharply localized and presumably were generated by impulse discharges from the cell somata. The characteristics of their responses described below sharply distinguished them from Purkinje cells. 2. The parallel fibre volleys generated by surface stimulation of a folium evoked brief repetitive discharges that were graded in respect of frequency and number. Maximum responses had as many as 10 impulses at an initial frequency of 500/sec. 3. At brief test intervals there was facilitation of the response to a second parallel fibre volley; at about 50 msec it passed over to depression for over 500 msec. 4. Stimulation deep in the cerebellum in the region of the fastigial nucleus (juxta-fastigial, J.F.) evoked by synaptic action a single or double discharge, presumably by the mossy fibre-granule cell-parallel fibre path, but climbing fibre stimulation from the inferior olive also usually had a weak excitatory action evoking never more than one impulse. 5. J.F. stimulation also had an inhibitory action on the repetitive discharge evoked by a parallel fibre volley. Possibly this is due to the inhibitory action of impulses in Purkinje cell axon collaterals. 6. There was a slow (7–30/sec) and rather irregular background discharge from all interneurones. The inhibitory actions of parallel fibre and J.F. stimulation silenced this discharge for some hundreds of milliseconds, probably by Golgi cell inhibition of a background mossy fibre input into granule cells. 7. All these various features were displayed by cells at depths from 180 to 500 μ; hence it was concluded that superficial stellate, basket and Golgi cells have similar properties, discrimination being possible only by depth, the respective depth ranges being superficial to 250μ, 250μ to 400μ, and deeper than 400μ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235206
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    Parallel fibre stimulation and the responses induced thereby in the Purkinje cells of the cerebellum (1966)
    Springer
    Experimental brain research 1 (1966), S. 17-39 
    Details
    ISSN: 1432-1106
    Keywords: Parallel fibres ; Purkinje cells ; Cerebellum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. When electrical stimuli were applied to the surface of a cerebellar folium by a local electrode (LOC), there was a propagated potential wave along the folium with a triphasic (positive-negative-positive) configuration. 2. Investigations by microelectrode recording established that this wave is produced by impulses propagating for at least 3 mm and at about 0.3 m/sec along a narrow superficial band or “beam” of parallel fibres. As expected from this interpretation, there was an absolutely refractory period of less than 1 msec and impulse annihilation by collision. 3. Complications occurred from the potential wave forms resulting from the excitation of mossy fibres by spreading of the applied LOC stimulus. These complications have been eliminated by chronically deafferenting the cerebellum. 4. When recording within the beam of excited parallel fibres there was a slow negative wave of about 20 msec duration, and deep and lateral thereto, there was a slow positive wave of approximately the same time course. 5. These potential fields were expressed in serial profile plots and in potential contour diagrams and shown to be explicable by the excitatory and inhibitory synaptic action on Purkinje cells: excitatory depolarizing synapses of parallel fibre impulses on the dendrites; and hyperpolarizing inhibitory synapses of stellate and basket cells respectively on the dendrites and somata. The active excitatory synapses would be strictly on the parallel fibre beam and the inhibitory concentrated deep and lateral thereto, which is in conformity with the axonal distributions of those basket and stellate cells that would be excited by the parallel fibre beam. 6. Complex problems were involved in interpretation of slow potentials produced by a second LOC stimulus at brief stimulus intervals and up to 50 msec: there was a potentiation of the slow negative wave, and often depression of the positive wave deep and lateral to the excited beam of parallel fibres. 7. Often the LOC stimulus evoked impulse discharge from the Purkinje cells, these discharges being inhibited by a preceding LOC stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235207
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    Spontane postsynaptische potentiale von nervenzellen des motorischen cortex der katze (1966)
    Springer
    Experimental brain research 1 (1966), S. 48-64 
    Details
    ISSN: 1432-1106
    Keywords: Spontaneous post-synaptic potentials (EPSPs, IPSPs) ; Motor cortex ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Im motorischen Cortex von ausgewachsenen Katzen (mittlere Nembutalnarkose) wurden spontane postsynaptische Potentiale (PSP) mit intrazellulären Mikroelektroden untersucht. Die spontanen EPSP wurden mit ausgelösten EPSP nach schwachen Reizen in spezifischen (VL) und unspezifischen (CM) Thalamuskernen verglichen. 2. Spontane EPSP treten entweder einzeln oder gruppiert auf. spontane IPSP sind seltener und machen nur 3–10% aller spontanen PSP aus. Die kleinsten EPSP haben eine Amplitude von 150–200 μV, daneben kommen kleinere, flache Schwankungen des Membranpotentials vor. Die mittlere Amplitude von spontanen EPSP liegt bei 0.7 mV. Amplitudenhistogramme spontaner EPSP unterscheiden sich nicht wesentlich von solchen, die durch schwache CM- oder VL-Reize ausgelöst sind. 3. Die Anstiegssteilheit von spontanen EPSP liegt zwischen 2 und 15 msec. Es besteht keine konstante Beziehung zwischen Amplitude und Anstiegssteilheit. Der Potentialabfall ist annähernd exponentiell, die Zeitkonstante liegt zwischen 8 und 12 msec und ist damit etwas länger als die passive Neuronzeitkonstante (8.5±2.2 msec nach Creutzfeldt u. Mitarb., 1964b). Es bestehen keine konstanten Unterschiede der Zeitverläufe von spontanen, durch VL- oder CM-Reiz ausgelösten EPSP-Einheiten. 4. Die Intervallhistogramme von spontanen EPSP sind verschieden je nach dem, ob alle Intervalle oder nur Perioden mit sporadischer, nicht-gruppierter Aktivität ausgezählt werden. Nicht gruppierte EPSP haben längere mittlere Intervalle (70–80 msec). 5. Nach überschwelligen Thalamusreizserien ist sowohl die spontane als auch die reizinduzierte PSP-aktivität vermindert. Es kann jedoch nicht entschieden werden, inwieweit corticale und inwieweit thalamische Mechanismen für diese post-tetanische Depression verantwortlich sind. 6. Während reversibler Deafferentierung des Cortex durch K+-depolarisation afferenter Fasern und im chronisch isolierten Cortex finden sich keine spontanen PSP mehr, obwohl EPSP und IPSP am isolierten Cortex durch epicorticale Reize noch ausgelöst werden können. 7. Aus den Befunden wird geschlossen, daß die beobachteten PSP durch afferente und collaterale Faseraktivität ausgelöst sind. Für echte „Miniaturpotentiale” entsprechend Beobachtungen an Muskelendplatten findet sich kein Anhalt. Insofern repräsentiert das „synaptische Rauschen” corticaler Zellen die konvergierende Afferenz dieser Zellen und kann nicht als echtes „spontanes Rauschen” angesehen werden.
    Notes: Summary Spontaneous post-synaptic potentials (PSP's) of neurones of the motor cortex are analysed (intracellular recording, Nembutal anesthesia, cats). Distinct EPSP's either appear grouped or more sporadically distributed. Spontaneous EPSP's only represent about 3–10% of all spontaneous PSP's. The mean amplitude of EPSP's is about 0.7 mV. The smallest EPSP's have an amplitude of 150–200 μV, smaller slow fluctuations of the membrane potential (MP) are seen occasionally. Amplitude histograms of spontaneous EPSP's are similar to those of evoked EPSP units following weak thalamic stimulation. — The rising time of spontaneous EPSP's varies between 2 and 15 msec. and is not correlated with the peak amplitude. The decay is almost exponential, the time constant is between 8 and 12msec., thus being slightly higher than the neurone time constant of cortical pyramidal cells (8.5±2.2 msec. Creutzfeldt et al., 1964b). No consistant differences in time course and amplitude of “EPSP units” after VL and CM thalamic stimulation and of spontaneous EPSP's was found. Cortical and thalamic components of post-tetanic depression of spontaneous and evoked PSP activity cannot be distinguished. Interval histograms are different whether all EPSP's during sporadic and grouped activity or whether only sporadically appearing EPSP's are counted. Non-grouped EPSP's show longer mean intervals (between 70 and 80 msec.). — During reversible deafferentation with K+-depolarization of afferent fibers and in the chronically isolated cortex no spontaneous EPSP's or IPSP's are found eventhough membrane fluctuations of cells in the latter preparation may sometimes be difficult to distinguish from real EPSP's. In the chronically isolated cortex, EPSP's and IPSP's can still be elicited by epicortical stimulation. — From these findings it is concluded that the observed spontaneous PSP's represent “unit” EPSP's and IPSP's due to afferent and collateral fiber activity and that no true miniature potentials due to spontaneous liberation of transmitter substance can be recorded. Thus, the “synaptic noise” of cortical neurones represents convergent activity on these cells and consequently cannot be considered as true “spontaneous noise”.
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    URL: http://dx.doi.org/10.1007/BF00235209
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