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  • 1
    Electronic Resource
    Electronic Resource
    Discharges of superior colliculus neurons during head and eye movements of the alert cat (1977)
    Springer
    Experimental brain research 27 (1977), S. 131-141 
    Details
    ISSN: 1432-1106
    Keywords: Colliculus superior ; Single neurons ; Eye movements ; Head movements ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 452 single neurons from the superior colliculus were recorded in awake and non-paralysed cats. 75 neurons were obtained from cats with unrestrained horizontal head movements. 228 neurons remained unaffected by saccadic eye movements. Eye movement related discharge followed the onset of saccades in 156 neurons either only in the presence of a visual pattern (92 neurons) or in darkness, too (64 neurons). The latter reaction type probably depends on eye muscle afferents. In 48 neurons eye movement related activity preceded the onset of eye movements. 12 neurons fired in synchrony with eye movements of any direction (type I). 30 neurons were excited during contralaterally directed eye versions within or into the contralateral head related hemifield. They were inhibited when the eyes moved within or into the ipsilateral head related hemifield (type II). 6 neurons with constant maintained activity during fixation were inhibited by ipsilaterally directed saccades, but remained unaffected by contralateral eye movements. Head movement related discharge followed the onset of head movements in 20 neurons only in presence of a visual pattern and also in darkness in 6 neurons. Ipsilateral head movements or postures strongly suppressed maintained activity and visual responsiveness of some neurons. 15 neurons discharged in synchrony with and prior to contralateral head movements. Ipsilateral head movements inhibited these neurons. Activation or inhibition were usually related to movement and to posture, exceptionally to movement or to posture. Electrical stimulation of recording sites of these neurons through the recording microelectrode elicits contralateral head movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237694
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  • 2
    Electronic Resource
    Electronic Resource
    Neuronale reaktionen im tectum opticum der katze auf bewegte und stationäre lichtreize (1967)
    Springer
    Experimental brain research 3 (1967), S. 353-367 
    Details
    ISSN: 1432-1106
    Keywords: Tectum opticum ; Movement detecting neurons ; Directional sensitive neurons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden 80 Einheiten des Tectum opticum der Katze abgeleitet und ihre Reaktionen auf stationäre und bewegte optische Reize geprüft. Neben den Neuronen, die in ihrer Reaktionsweise retinalen Einheiten vergleichbar waren, fanden sich überwiegend (89%) Neurone, die auf bewegte optische Reize reagierten. Unter den letzteren zeigte die Mehrheit (70%) richtungsspezifisches Verhalten. Bei einigen Neuronen war in einem beschränkten Bereich von 1–7.5∘/sec die Reaktion gesetzmäßig abhängig von der Winkelgeschwindigkeit des Bewegungsreizes (Potenzfunktion mit dem Exponenten 0.67). Die rezeptiven Felder waren meist rund mit einem durchschnittlichen Durchmesser von 8.1∘ (3–22∘). 68% der Einheiten reagierten nicht auf diffusen Lichtreiz. Die Reaktionen auf nicht bewegte Punktlichtreize waren rasch adaptierend und inkonstant in ihrer Art und Stärke. In kurzen Abständen mehrfach wiederholte Bewegungsreize bewirkten bei einem Teil der Bewegungsneurone rasche Adaptation. Zwei kurz aufeinander folgende Punktlichtreize ergaben eine Reaktion, die niedriger als die Summe der Erregungen der jeweils einzeln gegebenen Lichtreize war, wenn die zeitliche Folge der beiden Reize der Vorzugsrichtung des Neurons entgegengesetzt war. Bei Reizfolgen entsprechend der Vorzugsrichtung entsprach die Gesamtreaktion der Summe der Einzelreizantworten. Dies läßt vermuten, daß die Richtungsspezifität durch unilaterale Hemmung bedingt ist.
    Notes: Summary Recordings were made from 80 single units in cat's Tectum opticum during visual stimulation with moving and stationary optic stimuli. The majority of units (89%) showed movement specific reactions, the rest behaved functionally similar to retinal or geniculate neurons. 70% of the movement specific units showed directional selective reactions. The receptive fields, as determined with stationary and moving stimuli were mostly circular with an average diameter of 8.1° (range 3–22°). Stimuli passing through the periphery of the field led to less pronounced reactions than those going through the center. In 10 out of 30 units, the relation between discharge rate and angular velocity in a restricted range from 1°–7.5°/sec could be approximated by a power function with an exponent of 0.67. Above 10°/sec irregular and unsystematic alterations of reactivity were observed. 68% of the tectal units recorded did not respond to diffuse light stimuli. The reactions to localized intermittent stationary light stimuli were mostly off (42%) or on-off-responses (19%) and were characterized by fast adaptation, change of reaction type during successive intermittent stimulation and by the absence of an antagonistic field-structure. Stimulation of adjacent points in a temporal sequence corresponding to movement opposite to the most sensitive direction of a directional specific neuron led to a reaction which was below the sum of the reaction of the two stimuli given alone. At a temporal sequence of the two stimuli such as to simulate the most sensitive direction, the resulting reaction corresponded to the sum of the reactions of both stimuli given alone. This suggests a mechanism of unilateral inhibition to be responsible for directional selectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237560
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  • 3
    Electronic Resource
    Electronic Resource
    Activity of movement sensitive neurons of the cat's tectum opticum during spontaneous eye movements (1970)
    Springer
    Experimental brain research 11 (1970), S. 318-326 
    Details
    ISSN: 1432-1106
    Keywords: Movement detectors ; Tectum opticum ; Eye movements ; Retinal image shifts ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Activity of tectal movement specific neurons was recorded during spontaneous eye movements in total darkness and in presence of stationary visual stimuli. According to their reactions in presence or absence of stationary visual stimuli tectal units can be divided into four categories: 1. Neurons which are silent or discharge independently of eye movements, when the animal stays in total darkness, but which fire in synchrony with eye movements when stationary stimuli are presented. 2. Neurons which remain unaffected when the animal makes eye movements in total darkness or in presence of a stationary pattern. 3. Neurons which fire in synchrony with eye movements in absence and in presence of stationary patterns. In a few of these neurons tested curarization of the animal led to a marked increase of spontaneous activity. 4. Neurons whose spontaneous and stimulus driven discharge is suppressed in synchrony with eye movements when the animal is exposed to total darkness or when it faces stationary patterns
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01474390
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  • 4
    Electronic Resource
    Electronic Resource
    Influences of cortico-tectal and intertectal connections on visual responses in the cat's superior colliculus (1971)
    Springer
    Experimental brain research 12 (1971), S. 120-131 
    Details
    ISSN: 1432-1106
    Keywords: Superior colliculi ; Visual cortex ; Inhibitory interaction ; Cortical removal ; Direction selectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Our experiments, utilizing electrical shocks applied to the lateral- or supra-sylvian gyrus of the cortex, demonstrate an initially excitatory (latency 2–10 msec) but predominantly inhibitory influence of cortico-tectal afferents on the discharge of tectal neurons. Primary or secondary inhibition in tectal cells after cortical stimulation suppressed spontaneous or visually driven activity and limited the frequency of stimulation which tectal neurons could follow. The main influence of the contralateral colliculus on visual responses of tectal cells is inhibitory but again some principally monosynaptic intertectal connections evoked initial excitation (latency 3–10 msec) after electrical stimulation of the contralateral optic tract. Removal of the visual areas 17, 18 and 19 did not cause a loss of movement- or direction-selectivity in neurons of the superior colliculus. Cooling of the occipital cortex, while recording from direction-selective tectal neurons did not alter their essential response characteristics. The response to cortical shocks disappeared in tectal neurons during cooling but could be restored by rewarming of the cortex. It could not be confirmed in our experiments that excitation and movement- or direction-selectivity of neurons in the superior colliculus depend on a specific input from areas 17, 18 and 19 of the cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234310
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  • 5
    Electronic Resource
    Electronic Resource
    Aktivität von Neuronen im Tractus opticus und Corpus geniculatum laterale bei langdauernden Lichtreizen verschiedener Intensität (1966)
    Springer
    Biological cybernetics 3 (1966), S. 1-8 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Summary 1. The activity of single fibres of the optic tract (TO) und of neurones of the lateral geniculate body (CGL) was recorded during long lasting (4–10 min) diffuse light stimuli of different intensity (18–3500 lux) and during dark periods of the same length. The experiments were done on cats without general anestesia (operation under ether, curare). 2. At light on, most neurones of the TO as well as of the CGL showed, after an initial peak (on-, on-off-neurones) or an initial depression (off-neurones) of activity an almost exponential transition towards steady-state activity. This transitional period lasted 80–120 sec. Further analysis revealed two exponential parts, a first one whose course was independent from light intensity and which lasted 2–3 sec, and a second one whose steepness was dependent from the light intensity. At higher intensities, in on-neurones a triphasio course of adaptation was found with a significant depression of activity following the initial peak and a slow increase towards the steady state rate. The steady state discharge rate during illumination was above the dark activity in on-neurones, below in most on-off and all off-neurones. Some neurones (mainly with an on-center) only showed a short change of activity at light on and off but no lasting change of their activity during light. Since the majority of neurones with light-intensity-dependent steady state-discharge thus shows a decrease of activity during illumination (off- and most on-off neurones), Arduini's observation (1962) of a decrease of mass activity in TO and CGL during illumination is understandable. 3. The time course of adaptation of discharge activity of off-neurones at light off corresponded to that of on-neurones at light on. On- and off-center neurones did not behave completely reciprocal throughout the whole course of adaptation. 4. If in a given neurone the steady state discharge rate showed a systematic relation to light intensity this relation could be expressed by logarithmic functions as well as by power functions. This is valid for on-center- (positive exponent) as well as for off-center-neurones (negative exponent). On-center-neurones in the geniculate, however, may show a non-linear relation with two functions of different steepness at low and high light intensities. The validity of power- as well as of logarithmic functions is due to the similarity of both functions found in these experiments. 5. Differences in the behaviour of TO and CGL-neurones are shown. These consist mainly of a faster adaptation and lower discharge rate of CGL neurones at all intensities so that the relation between light intensity and discharge activity in the CGL is reduced by a linear factor compared to that in the TO. Besides this, qualitative differences exist in the steady state discharge activity with a tendency towards grouped firing in the geniculate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291083
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  • 6
    Electronic Resource
    Electronic Resource
    Effect ofd-amphetamine on the activity of single neurons of the cat's tectum opticum (1969)
    Springer
    Cellular and molecular life sciences 25 (1969), S. 373-373 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung d-Amphetamin (2–4 mg i.v.) verstärkt bei Neuronen des Tectum opticum der Katze die Reizantwort auf optische Bewegungsreize und vermindert oder beseitigt die während einer Reizfolge auftretende neuronale Adaptation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01899926
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  • 7
    Electronic Resource
    Electronic Resource
    The effects of focal epileptic activity on the somatosensory evoked potentials in the rat (1981)
    Springer
    European archives of psychiatry and clinical neuroscience 231 (1981), S. 81-91 
    Details
    ISSN: 1433-8491
    Keywords: Focal epilepsy ; Penicillin focus ; Somatosensory evoked potential ; Rat ; Focale Epilepsie ; Sensorische evozierte Potentiale ; Penicillinepilepsy ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Corticale, durch elektrische Vorderpfotenreizung evozierte somatosensorische Potentiale (SEP) der Ratte bestehen aus früzhen (P 1 und N 1) und späteren (P 2 und N 2) Komponenten. Mikroelektrodenableitungen ergeben unter denselben Reizbedingungen Einzelneuronenantworten kurzer und längerer Latenzen synchron mit den frühen (P 1, N 1) bzw. späten Komponenten (P 2). Im Verlauf einer durch topische Penicillin-Applikation erzeugten Focalepilepsie vergrößern sich nur die Amplituden der späten SEP-Komponenten. Mit der Größenzunahme der späten Komponenten verlängert sich die Entladungsdauer der Einzelneuronenantworten entsprechender längerer Latenzen. Die frühen SEP-Komponenten und die entsprechenden Einzelneuronenantworten kurzer Latenz bleiben unverändert. Im Cortex und in den sensorichen Relaisstationen (N. cuneatus, spezif. Kern des Thalamus) werden von 100 (N. cuneatus) bis zu 300 ms (Thalamus und Cortex) nach einem epileptischen Spike die somatosensorischen Potentiale partiell oder komplett unterdrückt. Der zeitliche Verlauf der Normalisierung der Amplituden ist für die frühen Komponenten thalamischer und corticaler SEP gleich, jedoch gegenüber den späteren corticalen Komponenten initial rascher. Unsere Befunde berechtigen zur Annahme zweier Gruppen somatosensorischer corticaler Neuronaktivität, deren Erregung frühe bzw. spätere Komponenten des SEP erzeugt und die unterschiedlich vom epileptogenen Agens beeinflußt werden.
    Notes: Summary The cortical somatosensory evoked potential (SEP) of the rat, evoked by contralateral forepaw stimulation, consisted of early (P 1 and N 1) and late components (P 2 and N 2). Microelectrode recording yielded evoked unitary responses of short latencies in the range of the early components and responses of longer latencies in the range of P 2. During the development of focal epilepsy after topical application of penicillin, the late components of SEP were enhanced and the enhanced late negativity corresponded to a surface negative cortical spike. The prominent enlargement of later components was associated with prolonged, often recurrent discharges of longer latency unitary responses and with enlarged local field potentials. Early components of SEP remained relatively unaffected and so did unitary responses with short latencies. Epileptic spike-conditioned SEPs in the cuneate nucleus, thalamic sensory relay nucleus and sensory cortex were depressed from 100 ms (cuneate nucleus) to about 300 ms (thalamus and cortex) subsequent to spike discharge. Transmission in the cuneate nucleus was least affected. Thalamic and cortical early components of SEP had similar time courses of recovery, which differed markedly from that of cortical late components. Our findings suggest that two different neuronal activities generate different components of SEP and are differentially involved in the epileptic activities, which results in the different amplitude recovery following spontaneous epileptic spike discharges.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00342832
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  • 8
    Electronic Resource
    Electronic Resource
    Slow potentials in the human subthalamus associated with rapid arm movements (1981)
    Springer
    European archives of psychiatry and clinical neuroscience 230 (1981), S. 41-47 
    Details
    ISSN: 1433-8491
    Keywords: Slow potentials ; Human subthalamus ; Cerebellothalamic connection ; Rapid arm movements ; Dely after coagulation ; Langsame Potentiale ; Subthalamus ; Kleinhirn-Thalamus-Verbindung ; Rasche Armbewegung ; Verzögerung nach Koagulation ; Mensch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Während stereotaktischer Operationen wurde in der Zona incerta von Parkinson-Patienten am Zielpunkt der Koagulation das EEG abgeleitet. Wenn der Patient spontan oder auf Lichtsignal hin eine rasche Beugung des kontralateralen Ellbogengelenkes ausführte, ließ sich in der Subthalamus-Ableitung ein langsames positives oder positiv-negatives Potential registrieren. Dieses begann 30–130 ms (Durchschnitt 60 ms) vor der EMGAktivierung des Bizeps und erreichte sein Maximum am Ende der initialen Bizeps-Aktivierung. Das Lichtsignal allein, ipsilaterale aktive oder kontralaterale passive Beugung konnten das Potential nicht erzeugen. Das Potential wird als Korrelat eines Startsignals für rasche Armbewegungen in cerebellothalamischen Bahnen gedeutet. Eine deutliche Verzögerung des Beginns der kontralateralen Bizepsaktivierung nach Koagulation des Ableitortes stützt diese Hypothese.
    Notes: Summary During stereotactic operations brain potentials were recorded from the zona incerta of Parkinsonian patients. When the patient performed a rapid contralateral elbow flexion in response to a light signal, a slow positive or positive-negative EEG potential preceded the EMG activation by 30–130 ms (average 60 ms) and extended into the biceps activation phase. It was not evoked by the light flash alone or by rapid passive flexion. The potential may be interpreted as a correlate of movement-related activity of cerebellothalamic pathways mediating command signals for rapid arm movements. In support of this assumption, a marked delay of contralateral biceps activation followed coagulation of the recording site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343765
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of iontophoretically applied biogenic amines and of cholinomimetic substances upon the activity of neurons in the superior colliculus and mesencephalic reticular formation of the cat (1971)
    Springer
    Pflügers Archiv 324 (1971), S. 43-55 
    Details
    ISSN: 1432-2013
    Keywords: Biogenic Amines ; Cholinomimetic Substances ; Microelectrophoresis ; Colliculus Superior ; Mesencephalic Reticular Formation ; Biogene Amine ; Cholinomimetica ; Mikroelektrophorese ; Colliculus Superior ; Mesencephale Retikulärformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The effects of iontophoretically applied cholinomimetic substances and of biogenic amines were tested in movement sensitive neurons of the colliculus superior and in neurons of the subtectal mesencephalic reticular formation. 2. Most collicular neurons were strongly excited by Glutamate which prevented neuronal adaptation and restored excitability in totally habituated neurons. GABA proved to be a strong depressant of collicular neurons. 3. Serotonine, Noradrenaline and Dopamine effectively depressed spontaneous, Gl-induced and stimulus driven activity of collicular units. Some units were selectively responsive to Serotonine, or to Catecholamines; others responded equally well to either group of substances. This suggests the existence of separate Serotonine respectively Catecholamine receptors. 4. Only a small proportion of collicular units (7%) was excited or depressed by cholinomimetic substrances. 5. The pharmacological properties of reticular units corresponded essentially to those of collicular neurons: GABA, Serotonine, Noradrenaline and Dopamine proved to be strong depressants of spontaneous, Gl-induced and stimulus driven activity. Selective responsiveness to Serotonine or to Catecholamines was found in some neurons. Cholinomimetic substances failed to influence a significant proportion of reticular units. Glutamate application produced strong excitation and led to an increase of somato-sensory receptive fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587795
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  • 10
    Electronic Resource
    Electronic Resource
    The inhibition of retinal ganglion cells by catecholeamines and γ-aminobutyric acid (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 45-54 
    Details
    ISSN: 1432-2013
    Keywords: Catecholamines ; GABA ; Microelectrophoresis ; Retinal Ganglion Cell Activity ; Katecholamine ; GABA ; Mikroelektrophorese ; Aktivität retinaler Ganglienzellen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. l-Dopa, the metabolic precursor of Dopamine, was found to depress the amplitude of the evoked potential in the optic tract, when applied intravenously. 2. Electrophoretic application of Dopamine on retinal ganglion cells produced inhibition of spontaneous and light driven activity, increase of latency of light evoked excitation and occasional suppression of the antidromic invasion. Dopamine and Glutamate interacted in an antagonistic manner. 3. Noradrenaline andd-Amphetamine were likewise effective in depressing spontaneous and induced activity of ganglion cells. Serotonine was ineffective or weakly depressant. 4. The effect of electrophoretically applied GABA was similar to that of Dopamine. It differed by a faster onset, quicker reversibility and slight diminuition with time. 5. Substances suspected to be transmitters by virtue of their presence in the retina are thus shown to produce the expected pharmacological effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00588530
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