Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2020-2023
  • 1985-1989  (32)
  • 1965-1969  (32)
  • 1986  (32)
  • 1969  (28)
  • 1966  (4)
  • Cat
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 69 (1986), S. 17-22 
    ISSN: 1432-0533
    Keywords: Brain abscess ; Cat ; Energy state ; Substrate mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Brain abscesses were induced experimentally in six cats by stereotactic inoculation ofStaphylococcus aureus A8 into the white matter of the left cerebral hemisphere. Seven days later, the brains were frozen in situ with liquid nitrogen and subsequently sawn into coronal sections of 5 mm thickness, while being cooled with liquid nitrogen. Thin slices were taken from those sections containing the largest expanse of abscess: slices of 5 μm thickness were stained histologically, and in adjacent 20 μm slices the regional distribution of ATP and glucose was mapped using substrate-specific bioluminescence methods. Furthermore, the NADH fluorescence from the surface of the tissue section was recorded. Six layers could be distinguished histologically in the abscess capsule, five of which showed different substrate patterns. Only in two layers a low metabolic activity could be observed, as shown by slight ATP bioluminescence. The pattern of the biochemical substrates in the white matter surrounding the abscess indicated a reduction in the cellular oxygen availability.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 173 (1986), S. 323-342 
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Corpus callosum ; Anterior commissure ; Columns ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This investigation had four goals: First, to study the general topography of the corpus callosum (CC) of the cat. Second, to study the columnar organization of CC terminals and map their banding pattern in the cortex. Third, to examine the relation between CC neuron density and the presence of CC terminal columns. Fourth, to determine whether CC and anterior commissure (AC) neuron distributions are intermixed. Eight adult cats were subjected to partial commissurotomies, and then to large injections of horseradish peroxidase to one cerebral hemisphere. Processing with tetramethyl benzidine revealed retrogradely labelled cells and anterogradely labelled terminals in the cortex of the uninjected hemisphere. The distributions of these cells and terminals were examined by light microscopy and analyzed by computer microscopic methods. The genu of the CC interconnects frontal portions of the cortex, the body interconnects mostly dorsal portions of the cortex, while the splenium interconnects the temporal and occipital cortices. Reconstructions of the CC terminal columns reveal intricate banding patterns in several non-primary areas of the cortex. CC cell density is greater within than outside the terminal columns. CC and AC neurons intermix in the infragranular lavers of the neocortex.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 173 (1986), S. 371-376 
    ISSN: 1432-0568
    Keywords: Motilin-like immunoreactivity ; RIA ; HPLC ; Cat ; Intestine ; Rat ; Cerebellum ; Purkinje cells ; Dendrites ; Neocortex ; Pyramidal cells ; Hippocampus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motilin was demonstrated by the immunoperoxidase technique in endocrine cells of the gastrointestinal tract using several specific antisera. Motilin-like immunoreactivity could only be demonstrated with one of these antisera and was observed in Purkinje cells and dendrites of the cerebellum, in pyramidal cells and dendrites of the cerebral cortex and in dendrites of the CA3 field of the hippocampus of the rat. Very low motilin-like immunoreactivity was found in cerebellum as well as in cerebral cortex using radioimmunoassay. However, using reverse phase liquid chromatography combined with UV-detection and radioimmunoassay, no peak of a peptide corresponding to synthetic motilin was detectable in rat cerebellar extracts, in contrast to findings in rat duodenum. The results do not suggest that motilin is an intrinsic neuroactive substance of the cerebellum.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 175 (1986), S. 261-269 
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Edinger-Westphal nucleus ; Retrograde transport of WGA-HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By means of retrograde axonal transport of the wheat germ agglutinin — horseradish peroxidase complex, a projection from the Edinger-Westphal nucleus to the lateral reticular nucleus was demonstrated in the cat. Following small tracer ejections in the main part of the lateral reticular nucleus, a significant number of labelled neurons were found bilaterally throughout the Edinger-Westphal nucleus. Most of the labelled cells were located on the ipsilateral side. The projecting neurons are spindle-shaped to round with a maximum diameter of the cell body between 15 and 30 μm. The findings are discussed in relation to other Edinger-Westphal efferent projections, and some comments are made concerning the cytoarchitecture and delineation of the feline Edinger-Westphal nucleus.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 62 (1986), S. 479-485 
    ISSN: 1432-1106
    Keywords: Cat ; Double labelling ; Fluorescent tracing ; Lateral cervical nucleus ; Ascending and descending neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The organization of ascending and descending neurones of the lateral cervical nucleus (LCN) was investigated in 10 adult cats after injections of the fluorescent tracers Fast Blue and Nuclear Yellow. Injections into the thalamus and tectum resulted in up to 3000 labelled cell profiles within the contralateral LCN. This corresponded to a calculated number of 4500 labelled LCN neurones. The greatest diameter of the labelled cell profiles was about 30 μm. They were located throughout the nucleus, but were less numerous in its medial portion. Injections mainly into the dorsal horn of different pairs of cervical and lumbar segments of the spinal cord resulted in a calculated number of up to 305 labelled LCN cells. The diameter of these cell profiles was about 25 μm and they were mainly situated in the rostro-ventral and medial parts of the LCN. Doublelabelled cells with ascending and descending projections were not encountered after injections into the thalamus-tectum and spinal segments C5-6. About 15% of the descending LCN cells were doublelabelled by pairs of spinal injections separated by intervals of one segment. It is concluded that the neurones descending down the spinal cord and ascending to the thalamus-tectum constitute different subpopulations of cells within the LCN and that a minor proportion of the descending cells seem to project to at least three adjacent segments of the spinal cord.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 280-290 
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Phrenic nerve ; Phrenic motoneurones ; Medullary pyramids ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Short latency responses were recorded from C5 phrenic roots and intracellularly from phrenic motoneurones following stimulation of the pericruciate cortex or medullary pyramids in cats anaesthetized with Nembutal or chloralose-urethane. Focal stimulation of the cortical surface (single pulses, 0.5–2 ms, 0.3–8 mA) during inspiration evoked EPSPs (latency 4.7 ± 1.7 ms, rise time 1.9 ± 1.1 ms, amplitude 0.22 to 3.94 mV) in 42% of motoneurones studied (n = 107). The EPSPs were absent, or on average 60% smaller, following stimulation during expiration. In all but two motoneurones, during both inspiration and expiration, hyperpolarizing potentials were observed either following the initial depolarization or alone. They could be reversed by hyperpolarizing current or chloride injection. Stimulation of the pyramidal tract at mid medullary level (1 to 3 pulses, 0.2 ms) evoked short latency excitation in phrenic motoneurones only with currents of more than 200 μA. Smaller stimuli applied to the medial reticular formation above the pyramidal tract evoked excitation (onset latency 1.5–3.2 ms) in which the earliest part was probably monosynaptic. These results show that the corticospinal responses in phrenic motoneurones are both excitatory and inhibitory. They are not transmitted through the pyramidal tract and are at least disynaptic. Excitation evoked from the medullary pyramidal tract can be explained by current spread beyond the pyramidal tract fibres.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 63 (1986), S. 443-448 
    ISSN: 1432-1106
    Keywords: Visual cortex (area 17) ; Intrinsic connections ; Visual deprivation ; Development ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracortical injections of horseradish peroxidase conjugated with wheat-germ agglutinin (WGA-HRP) reveal a characteristic patchy staining pattern within the superficial layers of cat striate cortex. The patches consist of a dense accumulation of labeled neurons and axonal arborizations. We have investigated the tangential organization and the development of these intrinsic cortical connections by using a flat-mount preparation of area 17. The diameter of the patches varied from 200 to 400 μm, the center-to-center distance ranged from 400 to 800 μm, and the spread of patches extended further in the anterior-posterior than in the medial-lateral direction. The expression of these horizontal patchy connections is age- and experience-dependent. From ten days to six weeks of age patches are exuberant and on occasion fuse to beaded bands extending radially from the injection site. From 6 weeks onwards the number and the tangential spread of the patches decreases to one or two rows of isolated clusters. Long-term binocular deprivation disrupts this pattern of intrinsic connections nearly completely. We infer from these results that there is an inborn pattern of discrete horizontal connections in striate cortex which is shaped by visual experience and requires contour vision for its maintenance.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 62 (1986), S. 273-280 
    ISSN: 1432-1106
    Keywords: Motoneurons ; Interactions ; Cholinergic synapses ; Phrenic nerve ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Interactions between phrenic motoneurons have been analysed in anaesthetized, paralyzed cats after C3 to C7 deafferentation. Effects of electrical stimulation of the C5 phrenic axons have been studied on thin filaments dissected from the stimulated nerve. Repetitive stimulation could elicit, after the primary direct response of the stimulated axons, a secondary response named Recurrent Response, RR. 2. RRs have been obtained in 117/186 phrenic axons. They appear sporadically (mean occurrence: 3.75 RRs elicited by 100 shocks of stimulation) at a constant latency. They originate from a spinal mechanism since they persist after C2 transection and disappear after section of the ventral roots. 3. The mechanism responsible for RR shows spatial and temporal facilitation. The RR probability increases with the number of antidromically invaded motoneurons as revealed by changes either of stimulation intensity or of central respiratory drive. However, RR could be evoked in a motoneuron without an antidromic volley in its axon. 4. Systemic injections of nicotinic blocking drugs such as dihydro-β-erytroidin or mecamylamine decrease or suppress the occurrence of RR; therefore, cholinergic synapses are involved in the RR generating process. 5. RR are assumed to be due to direct excitatory interactions between homonymous motoneurons. Recurrent axon collaterals impinging directly on neighbouring motoneurons would link together the different motoneurons of the phrenic pool. The functional significance of this phenomenon is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 62 (1986), S. 281-292 
    ISSN: 1432-1106
    Keywords: PT cell ; Areas 4γ and 5 ; Intracortical microstimulation ; HRP ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The cortico-cortical projection from area 5 to area 4 γ was studied in anesthetized cats. 2. Intracortical microstimulation of area 5 produced EPSPs in pyramidal tract (PT) cells in area 4 γ. Such EPSPs were analysed in a total of 54 fast PT cells. The rising phase of these EPSPs was often composed of fast and slow components. 3. Fast-rising EPSPs (fast component) were produced predominantly by stimulation within layer III of area 5 while slow-rising EPSPs (slow component) were evoked predominantly by stimulation within layer V of area 5. 4. The amplitudes of the fast and slow components of EPSPs produced during repetitive stimulation within layers III and V of area 5 decreased and increased, respectively, with an increase in the stimulus frequency without any appreciable changes in their latency and time-to-peak. The slow component was much less influenced by membrane hyperpolarization than the fast component. 5. Retrogradely labeled neurons were found not only in layer III but also in layer V of area 5 following HRP injection centered on superficial layers (I–III) of area 4γ. 6. It is suggested that there are two groups of cortico-cortical neurons in layers III and V of area 5, which may make monosynaptic contact with the proximal and distal sites of fast PT cells in area 4γ, respectively.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 585-596 
    ISSN: 1432-1106
    Keywords: Cat ; Chloralose ; Motor cortex ; PT collaterals ; Macro- and microstimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stimulating electrodes were placed in the red nucleus, lateral hypothalamus and medial thalamus in order to determine whether pyramidal tract (PT) neurons send collaterals to those sites. The red nucleus projections are well-known, but it was discovered that PT neurons also project into the other two sites. All of the fibers that sent collaterals to all three sites originated from fast PT neurons. Those that responded to stimulation of the skin and that sent collaterals to two or three sites were predominantly fast PT neurons. Those neurons that responded only to cerebral peduncle stimulation were predominantly slowly-conducting, when compared with the set of PT neurons in response to cerebral peduncle stimulation. The patterns of collateral branching to red nucleus and to lateral hypothalamus were similar, suggestimg a similar synaptic effect of the pyramidal system in the two sites. Measurement of the speed of conduction from three sites along the length of corticospinal fibers revealed large changes on some, but not all, fibers; there was no evident pattern to these changes that might be associated with collateral branching. A new hypothesis concerning the functional role of fast PT neurons in regulating movement is presented.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 625-637 
    ISSN: 1432-1106
    Keywords: Respiratory neurons ; Cervical spinal cord ; Axonal projection ; Phrenic motoneurons ; Intercostal motoneurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was performed in order to describe the location, axonal projection and possible synaptic action of the inspiratory neurons recently described in the upper cervical cord. In 26 cats anaesthetized with Nembutal, extracellular recordings were made from 224 cervical inspiratory units which were found near the lateral border of lamina VII and formed a column extending from the caudal end of the nucleus retroambigualis at the C1 segment to the rostral half of the C3 segment. Most of the units (approximately 85%) could be excited antidromically from the thoracic cord. Antidromic mapping showed collateral branches to the C5 segment in the vicinity of the phrenic nucleus, occasionally crossing the midline. No synaptic connections with phrenic motoneurones could be revealed either by cross-correlation of the activity of the cervical units with the discharge of C5 phrenic root, or by spike-triggered averaging (STA) of the post-synaptic noise recorded intracellularly from phrenic motoneurons. Extensive branching was found in the examined T3–T5 segments with arborizations near the ipsilateral intercostal motor nuclei and often extending across the midline. Cross-correlation experiments did not show clear monosynaptic connections to the inspiratory intercostal motoneurons. Intracellular recording from intercostal motoneurons and STA resulted in a few (2 out of 37) small, probably disynaptic, e.p.s.p.s. It is concluded that the upper cervical neurons are involved in the control of phrenic and intercostal motoneurons, probably through a disynaptic pathway involving segmental interneurons.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1432-1106
    Keywords: Antibodies to serotonin ; Immunocytochemistry ; Radioimmunoassay ; Antibodies specificity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Antibodies to 5-hydroxytryptamine (5-HT) were obtained from 4 rabbits after injections of 5-HT coupled to bovine serum albumin by means of paraformaldehyde (PF). Two methods were used to monitor the developement of antibodies (AB): the one based on the “in vitro” competitive binding properties of the antibodies with3(H)5-HT, the other, on their “in situ” binding properties to endogenous 5-HT, using the peroxidase-anti-peroxidase immunohistochemical technique, applied to paraffin embedded sections of cat brainstem. No pharmacological processing, detergents or proteolytic enzymes were used. The specificity of the antiserum was tested by competitive procedures with 20 analogs using the “in vitro” and “in situ” techniques. “In vitro” studies were performed with 5-HT free analogs and with analogs previously coupled with PF to lysine. Radioimmunological tests showed that the antibodies recognize mainly the ethylamine (CH2-CH2-NH2)-cham of the free analogs and that the best specificity was obtained with the 5-HT conjugate (5-HT-lysine-PF). The results suggest that the hapten is coupled through the phenolic positions C4 or C5. The “in situ” immunohistochemical extinction assays also revealed a distinct specificity for 5-HT. Possible optical and ultrastructural applications are illustrated in the raphé nuclei of the cat. These results confirm the reliability of radioimmunological tests for studying the specificity of AB directed against haptens, provided that haptens and analogs tested were first chemically transformed to resemble the immunogen (herewith lysine-PF coupling) with regard to its antigenic structure.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 62 (1986), S. 486-494 
    ISSN: 1432-1106
    Keywords: Mechanoreceptors ; Thresholds ; Stimulus-response functions ; Cuneatus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response characteristics of mechanoreceptive neurons (RA, SA, and PC) innervating the foot pad of cat were determined in the cuneate nucleus. The mechanical stimuli were single sinusoidal pulses of varying frequency (20, 60, 150, and 240 Hz), and vibratory trains of varying frequency (80 and 240 Hz) and duration (50, 100, and 400 ms). Thresholds and stimulus-response functions were determined with single pulses. Absolute thresholds (1 impulse/train), tuning thresholds (1 impulse/cycle), and atonal intervals (the range between absolute and tuning thresholds) were determined with vibratory stimulus trains. When tested with single pulses the thresholds resembled those of primary afferents in all unit populations. The stimulus-response function of PC units but not of all RA units were comparable to those of primary afferents. Noxious conditioning stimulation did not influence the thresholds of cuneate mechanoreceptors in the tested sample (N = 6). Mostly PC units were tested with vibratory trains. Absolute thresholds were not dependent on stimulus duration, which is a consistent finding with peripheral units. In contrast to peripheral units, the tuning thresholds in most PC units were elevated with increasing stimulus duration. The variability in the range of atonal intervals was much larger than in the periphery. Thus, it seems that both the type of the tactile signal and the type of the studied mechanoreceptive neuron are critical parameters in determining whether the response characteristics of neurons in the cuneate and in the periphery are identical or not.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 432-437 
    ISSN: 1432-1106
    Keywords: Claustrum ; Putamen ; Auditory response properties ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The auditory response properties of single neurons in claustrum and putamen were studied in response to simple dichotic stimuli (viz. noise- and tone-bursts) in chloralose-anaesthetized cats. Neurons in claustrum were commonly weakly driven with long latency, were broadly tuned and were excited by stimulation of either ear (EE). Putamen neurons, in contrast, were securely driven with short latency, showed irregular tuning with a preference for low frequencies and were either EE or excited only by the contralateral ear (EO). The differences between claustrum and putamen responses can be related to differences in connections with the auditory cortical fields and with auditory thalamus. Some neurons were also tested for visual responsiveness: auditory and visual cells were intermingled in both nuclei and only a small percentage of cells were bimodal. In contrast to the visual and somatosensory input to claustrum, which are derived from primary cortical fields, the auditory input to claustrum is apparently derived from non-primary cortical regions, suggesting a fundamentally different role for processing of auditory information in claustrum.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 447-450 
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Single units ; Eye movements ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single unit activity was studied in the intermediate and deep layers of the superior colliculus in two trained cats. Eye movements were recorded with a magnetic search coil, the head being fixed. Discharge rates which varied as a function of eye position were consistently observed in 7 of 67 (about 10%) of the sample of eye movement-related units. These units showed similar changes in firing rate as a function of eye position in total darkness and during task related fixation of visual targets and thus appear to convey an “eye position” signal. Their activity may originate either from proprioception or from corollary discharge.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 63 (1986), S. 581-584 
    ISSN: 1432-1106
    Keywords: Visual neurons ; Contrast ; Binocular interactions ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dichoptic presentation of patterns similar in shape but of very different contrast results in the perception of only the high contrast pattern (binocular suppression). When recording from binocular neurons of the cat visual cortex, we have found an effect which is strikingly similar to this perceptual phenomenon. If a high and a low contrast grating are presented simultaneously, one to each eye, the cell's response to the low contrast stimulus is suppressed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 65 (1986), S. 98-111 
    ISSN: 1432-1106
    Keywords: Cat ; Interneurones ; Motor control ; Jaw movements ; WGA-HRP ; Retrograde transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The location of bulbar neurones with axons projecting to the ipsi- and contralateral trigeminal motor nucleus were investigated in cats anaesthetized with sodium pentobarbital. Wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected in amounts of 5–24 nl. A volume-calibrated microelectrode was used for recording of evoked potentials and pressure injection of WGA-HRP. The injection site was guided by the position where a maximal antidromic response was evoked by electrical stimulation of the masseteric nerve. The survival time was 19–22 h. In preparations with the depot located in the masseteric subnucleus retrogradely stained neurones were found bilaterally in the borderzone of the trigeminal motor nucleus. Dense populations of stained neurones were observed ipsi- and contralaterally in the dorsal division of the main sensory trigeminal nucleus and the subnucleus-γ of the oral nucleus of the spinal trigeminal tract. Clusters of WGA-HRP-neurones were observed bilaterally in the lateral tegmental field at the level of the subnucleus-β of the oral nucleus of the spinal trigeminal tract, bilaterally dorsal to the facial nucleus and contralaterally adjacent to the hypoglossal nucleus. No stained neurones were found in the gigantocellular reticular nucleus. A group of stained neurones was located in the marginal nucleus of brachium conjunctivum and some were found in the raphé nuclei near obex. Cell profiles were of two types: medium-sized neurones with a triangular profile and 30–40 μm diameter, and fusiform neurones 10×50–70 μm. Convergence of descending cortical and trigeminal afferent inputs on interneurones located in the lateral borderzone of the trigeminal motor nucleus, i.e. the intertrigeminal area, is reported in the preceding paper.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 272-279 
    ISSN: 1432-1106
    Keywords: Membrane property ; Postsynaptic potentials ; Axotomized trigeminal motoneuron ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The membrane properties and the efficacy of excitatory and inhibitory synapses were studied in cat masseteric motoneurons (Mass Mns) after axotomy. In axotomized Mass Mns the slope of the primary range in the frequency-current relationship showed a higher gain than that of normal Mass Mns. The safety of antidromic invasion was increased and the initial segment component of antidromic action potentials could not be separated from the somadendritic component. In normal Mass Mns a single shock delivered to the orbital gyrus or the lingual nerve induced long-lasting inhibitory postsynaptic potentials (IPSPs). In two-thirds of Mass Mns explored 30 days after axotomy, a single shock delivered to the orbital gyrus or the lingual nerve evoked a mixture of inhibitory and excitatory synaptic potentials. In Mass Mns 50 days after axotomy, we have demonstrated that the major fraction of the total sample of explored Mass Mns showed long-lasting excitatory postsynaptic potentials followed by IPSPs. The results suggest that in Mass Mns, axotomy is followed by the decline of synaptic efficacy of inhibitory rather than of excitatory synapses.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 61 (1986), S. 303-310 
    ISSN: 1432-1106
    Keywords: Pyramidal tract axons ; Cat ; Size and morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this work was to determine the number and morphology of pyramidal tract (PT) axons in the cat, using electron microscopy, modern methods of fixation, and computer-assisted morphometric analysis. Sections taken at the level of the medullary pyramids in three animals were fixed and magnified up to 10,000 x to produce photomicrographs. Morphological data were entered into computer files for analysis by tracing axon perimeters on micrographs mounted on a digitizer tablet. The number of axons per PT averaged 415,000, of which 88% were myelinated and 12% were unmyelinated. 90% of the myelinated axons fell in the diameter range 0.5–4.5 μm. Axons larger than 9 μm diameter accounted for 1% of the total; the largest were 20–23 μm. Myelinated axon mean diameter was 1.98 μm; because of the skewed distribution, with many small axons and a few very large axons, median diameter was 1.60 μm. Size distribution was relatively uniform throughout the PT cross section, with all sizes represented in all regions. However, the more medial regions had a higher proportion of small fibers than the more lateral regions: mean medial diameter was 1.85 μm while mean lateral diameter was 2.09 μm. Myelin sheath thickness averaged 7.9% of fiber diameter for axons up to 11 μm, but was constant at 0.9 μm for larger fibers. Myelinated fibers were distorted from the circular shape in cross section, with a mean circularity index (or form factor) of 0.85, which implies that the fibers could swell about 15% without rupture of the cell membrane. Unmyelinated fibers averaged 0.18 μm diameter (range 0.05–0.6 μm); the largest unmyelinated axons were larger than the smallest myelinated axons. It is concluded that previous work greatly underestimated the number of axons in the cat pyramidal tract.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 63 (1986), S. 35-48 
    ISSN: 1432-1106
    Keywords: Semicircular canals ; Three-neuron arc ; Vestibulo-ocular reflex ; Horseradish peroxidase ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology of vertical canal related second order vestibular neurons in the cat was studied with the intracellular horseradish peroxidase method. Neurons were identified by their monosynaptic potentials following electrical stimulation via bipolar electrodes implanted into individual semicircular canal ampullae. Anterior and posterior canal neurons projected primarily to contralateral or ipsilateral motoneuron pools (excitatory and inhibitory pathways, respectively). The axons of contralaterally projecting neurons crossed the midline at the level of the abducens nucleus and bifurcated into an ascending and a descending main branch which travelled in the medial longitudinal fasciculus (MLF). Two types of anterior canal neurons were observed, one with unilateral and one with bilateral oculomotor projection sites. For both neuron classes, the major termination sites were in the. contralateral superior rectus and inferior oblique subdivisions of the oculomotor nucleus. In neurons which terminated bilaterally, major collaterals recrossed the midline within the oculomotor nucleus to reach the ipsilateral superior rectus motoneuron pool. Other, less extensive, termination sites of both neuron classes were in the contralateral vestibular nuclear complex, the facial nucleus, the medullary and pontine reticular formation, midline areas within and neighboring the raphé nuclei, and the trochlear nucleus. The ascending main axons continued further rostrally to reach the interstitial nucleus of Cajal and areas around the fasciculus retroflexus. The descending branches proceeded further caudal in the medial vestibulo-spinal tract but were not followed to their spinal target areas. In addition to two previously described posterior canal related neuron types (Graf et al. 1983), we found neurons with bilateral oculomotor terminals and a spinal collateral. Typical for posterior canal neurons, the major termination sites were in the trochlear nucleus (superior oblique motoneurons) and in the inferior rectus subdivision of the oculomotor nucleus. Axon collaterals recrossed the midline to reach ipsilateral inferior rectus motoneurons. The axons of ipsilaterally projecting neurons ascended through the reticular formation to join the MLF caudal to the trochlear nucleus. The main target sites of anterior canal related neurons were in the trochlear nucleus and the inferior rectus subdivision of the oculomotor nucleus. Minor collaterals reached the pontine reticular formation and areas in between the fiber bundles of the ipsilateral MLF. In some cases, small collaterals crossed the midline within the oculomotor nucleus to terminate in the inferior rectus subdivision on the contralateral side. The axon proceeded further rostral to project to the interstitial nucleus of Cajal and beyond. The main termination sites of posterior canal neurons were in the superior rectus and inferior oblique subdivisions of the oculomotor nucleus. Minor collaterals were also observed to reach the midline area within the oculomotor nucleus, however, prospective contralateral termination sites could not be identified. More rostral projections were found in the interstitial nucleus of Cajal. The described axonal arborization of second order vestibular neurons reflects the organization of intrinsic coordinate systems as exemplified by the geometry of the semicircular canal and the extraocular muscle planes. These neurons are interpreted to provide a matrix for coordinate system transformation, i.e. from vestibular into oculomotor reference frames, and to play a role in gaze control and related reflexes by distributing their signals to multiple termination sites.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 21
    ISSN: 1432-1106
    Keywords: Prefrontal cortex ; Limbic cortex ; Medial preoptic area ; Axonal branching ; Electrophysiology ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurons in cat medial prefrontal cortex, anterior limbic cortex and possibly the indusium griseum were identified by antidromic invasion as having axonal projections towards the medial preoptic region, using both macro- and microstimulation techniques. These projecting axons were found to be of slow conduction velocity (0.2–4.8 m/s) and to in some cases also send branches towards the anteromedial thalamus, mediodorsal thalamus, ventromedial tegmentum, basolateral amygdala or medial forebrain bundle. Threshold-depth curves for axons excited by microstimulation in the medial preoptic region were very steep, with proportionality constants of 0.3–7.1 μm/μA. Calculations based on the threshold-depth curves confirmed that microstimulation was most probably only activating axons within the MPO, and current spread to lateral fibers of passage following macrostimulation in the MPO was not detected in the branching studies.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 22
    ISSN: 1432-1106
    Keywords: Lateral suprasylvian cortex ; Posterior lateral suprasylvian area ; Topography ; Visual field representation ; Scatter of receptive fields ; Cat ; PMLS ; PLLS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the orderliness of representation of visual space in the medial and lateral banks of the middle suprasylvian sulcus. Penetrations were made either parallel to the sulcus, in one bank or the other, or vertical, thus crossing the sulcus between the postero-medial (PMLS) and posterolateral (PLLS) divisions of this area. In some cases we found clear evidence for topographical order in the representation of the visual field with a tendency (greater in PMLS than in PLLS) for the receptive fields of cells recorded deeper in the walls of the sulcus to lie closer to the area centralis, but along many penetrations the receptive fields were so large and so scattered that no retinotopic arrangement could be discerned. In PMLS the receptive fields of the majority of units we studied were centred below and close to the horizontal meridian, whereas in PLLS they were distributed over both the upper and lower visual fields with an over-representation of the upper field. Receptive fields were significantly larger in PLLS (mean field area = 442.2 deg2) than in PMLS (mean area = 154.4 deg2); there was also less clear correlation between receptive field size and eccentricity in PLLS (correlation coefficient = +0.25) than in PMLS (corr. coeff. = +0.72). Analysis of the distance between the receptive field centres of consecutively recorded units demonstrated that the mean scatter in both PMLS and PLLS amounts to about half the average receptive field diameter. In summary the topographical representation of visual space is less orderly in PLLS, and may involve a wider area of the visual field. These findings may relate to the segregated visual cortical and extrageniculate thalamic connections that the medial and lateral banks of the LS receive.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 23
    ISSN: 1432-1106
    Keywords: Locomotion ; Cat ; Hindlimb motoneurons ; Inhibition ; Excitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Intracellular recordings of various motoneurons of proximal hindlimb muscles were performed on thalamic paralyzed cats, during fictive locomotion that was either spontaneous or evoked by stimulation of the subthalamic region. 2. In motoneurons innervating sartorius (medialis and lateralis), vasti (intermedius, medialis and lateralis) and anterior biceps-semimembranous, one depolarization occurred in each locomotor cycle, alternating with a phase of repolarization that was synchronous with the activation of the antagonistic muscle nerve. This latter phase could be decreased or reversed by intracellular injection of chloride ions or current, revealing the presence of inhibitory inputs onto motoneurons. 3. The pattern of membrane potential variations was more complex in motoneurons of rectus femoris and posterior biceps-semitendinosus muscles, but phases of chloride dependent inhibition were nevertheless identified, mainly during the sartorius nerve activation in the case of rectus femoris, and during the vasti and anterior biceps-semimembranosus nerve activations in the case of posterior biceps-semitendinosus. These inhibitory influences were shown to be controlled by the level of activity in exteroceptive afferents. 4. The characteristics of the excitatory and inhibitory inputs to the hindlimb motoneurons identified here are discussed in relation with the organization of the central pattern generator for locomotion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 64 (1986), S. 233-236 
    ISSN: 1432-1106
    Keywords: Lateral geniculate nucleus ; Orientation bias ; Receptive field ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The orientation sensitivity of LGN cells to flickering square-wave gratings was measured in urethane-anaesthetized paralyzed cats. The mean ratio of the amplitude of peak responses to optimally oriented gratings to that elicited by gratings of the least effective orientation was 3.0 ± 0.3 (S.E.). 58% of the recorded neurons responded best to orientations within 30° of the meridional line joining their receptive field center with the fixation points (area centralis), implying that they were more sensitive to visual contours pointing to the center of the retina.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 1432-2013
    Keywords: Peripheral chemoreceptors ; Central chemoreceptors ; Control of respiration ; Dopamine ; Cat ; Hypercapnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of exogenous dopamine on the normoxic hypercapnic ventilatory response were assessed in nine chloralose-urethane anesthetized cats using the technique of dynamic end-tidal forcing. The ventilatory responses to step changes in end-tidalP CO 2 (PETCO 2) were measured before (control), during and after intravenous infusion of dopamine (420 μg·kg−1·h−1). Each response was separated into a slow central and a fast peripheral chemoreflex loop by fitting two exponential functions to the measured ventilation. Both loops were described by a CO2 sensitivity, time constant, time delay and a single off-set B (extrapolated PETCO 2, of the steady-state response curve at zero ventilation). Dopamine infusion only caused a significant increase of B (mean 0.3 kPa,P〈0.0001) compared to control; the other model parameters were not significantly affected. After dopamine infusion B returned to significantly lower values (mean 0.2 kPa,P=0.006) than in control. In two additional cats the dopamine administered to the blood which was artificially perfusing the brainstem, did not affect ventilation. We conclude that in normoxic cats the effect of exogenous dopamine on the ventilatory response to CO2 is due to a CO2 independent inhibition of the ventilatory drive which originates outside the brainstem.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 406 (1986), S. 419-423 
    ISSN: 1432-2013
    Keywords: Rabbit ; Cat ; Chemoreceptor ; Reserpine ; α-Methyl-p-tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The response of single chemoafferent fibres to hypoxic and hypercapnic stimulation was studied in vitro under different experimental conditions: 1. control, 2. 24 h after reserpinization (5 mg/kg iv) and 3. 18 h after iv injection of α-methyl-p-tyrosine (100 mg/kg in the rabbit, and 1. control and 2. 24 h after reserpinization (5 mg/kg ip) in the cat. The spontaneous activity was decreased by monoamine depletion. The amplitude of the response to hypoxia and to hypercapnia was decreased by reserpinization in the rabbit and in the cat, the change being less marked in the latter species. Similarly, treatment with·α-methyl-p-tyrosine decreased the ability of chemoreceptors to respond to hypoxia and hypercapnia and, in a few instances, these receptors could only be excited by superfusion of nitrogencquilibrated medium. These results emphasize to possible role of monoamine, and particularly dopamine, in modifying the sensitivity of arterial chemoreceptors to their natural stimuli.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1432-2013
    Keywords: Lumbar visceral afferents ; Urinary bladder ; Urethra ; Functional properties ; Visceral nociception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neural activity of lumbar visceral afferents supplying the urinary bladder and urethra was analyzed systematically in the cat. The afferent fibres were isolated either from the white rami L3 and L4 in a preparation with closed peritoneal cavity, or from the lumbar splanchnic nerves in a preparation with open peritoneal cavity and investigated for various functional parameters. Seventy five single units and 9 multiunit bundles were analyzed. 1) About 50% of the afferent units had some ongoing activity (0.2 to 1 imp/s). Two thirds of the afferent axons were thin myelinated (conduction velocity 3–15 m/s), the rest were presumably unmyelinated (conduction velocity below 2 m/s). 2) The receptive fields of the afferent units consisted —with one exception — of single mechanosensitive sites on the surface of the bladder and urethra. Most receptive fields were situated on the dorsal side of the bladder. 3) Afferents with receptive fields on or in the bladder wall responded in a graded manner to passive distension and isovolumetric contraction at intravesical pressures ranging from about 10 to 70 mm Hg. The thresholds for exciting the afferent units ranged from less than 10 mm Hg to about 30 mm Hg intravesical pressure, most of them being less than 20 mm Hg. Generally, the discharge rate of the afferent units gave a reliable representation of the intravesical pressure to the lumbar spinal cord. 4) Urethral units exhibited either no responses to the graded distensions and contractions of the urinary bladder, or responded with low discharge rates at higher intravesical pressures. 5) The results do not support the notion that noxious events in the urinary bladder are encoded by “specific” nociceptive visceral afferents to the lumbar spinal cord but possibly by some other mechanism of encoding.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1432-0878
    Keywords: Serotonin-immunoreactive nerve fibers ; Lateral geniculate nucleus ; Immunohistochemistry ; Rat ; Cat ; Monkey (Macaca fuscata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of serotonin-containing nerve fibers in the lateral geniculate nucleus (LGN) of the rat, cat, and monkey (Macaca fuscata) was studied by use of the peroxidase-antiperoxidase method and an antiserum against serotonin. In all three species, the pattern of fibers was denser in the ventral portion of the LGN (LGNv) than in the dorsal nuclear portion (LGNd). In the LGNd of rat, serotonin-immunoreactive fibers were evenly distributed in the form of a dense network, but in cat and monkey there were marked regional differences. Serotonin-immunoreactive elements were most numerous in the C complex and medial interlaminal nucleus of cat, and in the S layer and interlaminar zones of Macaca fuscata.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 246 (1986), S. 309-319 
    ISSN: 1432-0878
    Keywords: Muscle spindle ; Sensory innervation ; Mechanosensory transduction ; Morphogenesis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The arrangement of preterminal and terminal axon branches in the primary sensory endings of cat tenuissimus muscle spindles was studied using whole-mount and serial-section techniques. Although in every case one firstorder preterminal branch was supplied exclusively to the bag1 type of intrafusal muscle fibre, the preterminal branching patterns differed considerably in detail. Terminals varied widely in size and location. Their precise form varied according to their position on the intrafusal muscle fibres rather than their relationship to preterminal branches. Terminals derived from separate preterminal branches remained separate and did not fuse with themselves or each other. Individually bag1 fibres had most terminals, chain fibres least. The surface of the muscle fibres were differentially indented by the terminals, least in bag1 fibres and most in chain fibres. The results are discussed in relation to mechanosensory transduction and to the factors involved in determining the form of the primary ending.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1432-0878
    Keywords: Amino acid uptake ; Autoradiography ; Salivary gland ; Serine ; Phenylalanine ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light-microscopic autoradiography was used to localize the cellular sites for neutral amino acid uptake in submandibular and sublingual salivary gland epithelia. The vasculature of isolated glands was perfused for 3–5 min with either L-(3-3H)serine or L-(4-3H)phenylalanine and then fixed by perfusion with buffered glutaraldehyde. In the submandibular gland the small neutral amino acid L-serine and the aromatic amino acid L-phenylalanine were localized to central acinar cells, demilunar cells and ductal cells. In the sublingual gland silver grains associated with each of these tritiated amino acids were localized to central acinar and ductal cells. Perfusion of both submandibular and sublingual glands with unlabelled L-serine (25 mM) or L-phenylalanine (30 mM) resulted in a significant decrease in the silver grain density associated with each labelled amino acid. The absence of silver grains in the lumina of acinar and ductal cells and the presence of tight junctions near the apical surface of the epithelium strongly suggest that the initial uptake of these amino acids was mediated by basolateral plasma membrane carriers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 244 (1986), S. 197-202 
    ISSN: 1432-0878
    Keywords: Transverse tubular system ; Sarcoplasmic reticulum ; Triads ; Intrafusal muscle fibre ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A modified staining technique for transverse tubular and sarcoplasmic reticular systems was used to investigate their occurrence in different types of intrafusal muscle fibres in cat tail spindles. Intrafusal muscle fibres can be divided into three basic regions, namely, the periaxial space (A-region), intracapsular area (B-region) and the extracapsular area (C-region); the components of these systems were seen to vary in structure and distribution. The occurrence of these systems also varied among the different types of intrafusal muscle fibres, namely, the bag1, bag2 and chain fibres. In bag1 fibres components were sparse in the A-region, increased slightly in the B-region, but were most developed in the C-region; triads were consistently located at the border between A- and I-bands. In bag2 fibres membrane components were noted in the A-region but were more abundant in the B-region where some tubular components showed transverse and longitudinal branches linked together in the form of a network; membrane systems diminished towards the C-region. The majority of triads were located within the A-bands. In chain fibres the membrane systems occurred more commonly in the A-region, while in the B- and C-regions, the transverse tubular system possessed numerous transverse and longitudinal branches forming irregularly distributed tubular networks. Some tubular branches were dilated, while other branches terminated as sacs among arrays of the sarcoplasmic reticular system in I-bands. Some transverse tubules bifurcated into two branches with numbers of dilated sarcoplasmic reticular cisternae lying on either side, or between, the branches. Triads sometimes occurred between A- and I-bands, but, generally, were situated well within A-bands.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 55 (1986), S. 137-141 
    ISSN: 1439-6327
    Keywords: Weight-lifting exercise ; Cat ; Flexor carpi radialis muscle ; Nitric acid digestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of weight-lifting, which induced muscular enlargement, on fiber number was tested in the flexor carpi radialis muscle by operantly conditioning 6 cats to flex their right wrist against increasing resistance for an average of 101 weeks. The left was used as a control. At the end of training, the cats were performing “one-arm“ lifts with an average of 57% of their body weight. There was an 11% greater muscle weight (P〈0.01) and 9% (P〈0.02) more fibers in the exercised muscles from the right limb than in the left. This study using a different method, supports our earlier observations that prolonged weight-lifting exercise significantly increases the total number of muscle fibers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 36
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 42
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 43
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 47
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 49
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 51
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 55
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 2 (1966), S. 247-260 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 1 (1966), S. 1-16 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 1 (1966), S. 17-39 
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 1 (1966), S. 48-64 
    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”.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...