Involvement of visual specific and association cortex input in the shaping of neostriatal neuron response to visual stimulation in unanesthetized cats

During chronic experiments on unanesthetized cats neuronal response in the caudate nucleus to the presentation of local photic stimuli and electrical stimulation of the specific (field 17) and the association (Clare-Bishop) areas were compared. Stimulation of the Clare-Bishop area proved more effective than stimulating field 17 for neurons of the caudate nucleus; a response was produced in 47% of test neurons in comparison with 8% of units only in the specific area. Lower average values were observed for latency of neuronal response to stimulation of the Clare-Bishop area. An insignificant number of caudate nucleus neurons were activated as a result of stimulation of both cortical areas. A comparison between the response of one set of neurons to electrical cortical and visual stimulation showed that cells responding to visual stimulation were more highly activated by stimulating the Clare-Bishop area than by stimulation of field 17. This type of neuron predominated in the caudate nucleus. A discussion follows of the possible involvement of the Clare-Bishop area in shaping neuronal response to visual stimulation.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 17, No. 5, pp. 619–627, September–October, 1985.     

Neuronal response to sensory stimulation in the cat caudate nucleus

Neuronal response in the caudate nucleus to presentation of a wide variety of visual and other sensory stimuli was investigated in waking cats. Pronounced discrepancies in background activity of unknown origin as well as differing neuronal activity level were noted in adjacent sections of the nucleus. Of the neurons from which readings of response to sensory stimulation could be made, some reacted to presentation of exclusively visual and others to tactile stimuli; a third group responded to a combination of visual and somatic stimulation only. Response could only be produced in cells of all types by a high level of activity in the animal. Visual stimuli attracting the animal's interest proved to be the most effective form of stimulation. Ipsi- and contralateral sides of the animal's body were both represented in the caudate nucleus of each hemisphere. Neuronal response in the caudate nucleus may be compared with that produced by application of similar stimuli in cells belonging to different cortical areas.Institute for Research on Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 1, pp. 3–10, January–February, 1990.     

Responses of caudate neurons to clicks in chronic experiments on cats

Spontaneous and evoked unit activity in response to repeated application of clicks at a frequency of 0.3–2.0 Hz in the caudate nucleus was studied by an extracellular recording technique in chronic experiments on cats. Four types of spontaneous unit activity in the caudate nucleus were distinguished. Altogether 44% of neurons tested responded by changes in spontaneous activity to clicks. Five types of responses of caudate neurons to clicks were discovered: phasic excitation, phasic inhibition, tonic activation, tonic inhibition, and mixed tonic responses; the commonest type was tonic activation. During prolonged stimulation by clicks extinction of the phasic responses was not observed. Complete or partial extinction of tonic responses in the course of frequent repetition of stimulation was observed in 33% of responding neurons. The question of possible convergence of specific and nonspecific influences on caudate neurons is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 28–35, January–February, 1980.     

Distribution of neurons responding to sensory stimuli and organization of topic projections in the cat caudate nucleus

The distribution of neurons responding to presentation of different sensory stimuli was investigated during chronic experiments on cats. These showed that cells responding to somatic and visual stimulation were unevenly distributed and that areas with differing levels of activity within the same nucleus alternated. No single topic projection was identified within the structure reaching the entire nucleus. The findings were compared with those found during morphological research indicating heterogeneity in caudate nucleus structure, implying the existence of neuronal groupings (or striosomes) belonging to a topically organized projection from the animal's body.Institute for Research into Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 2, pp. 156–162, March–April, 1990.     

Unitary responses of the caudate nucleus to direct stimulation

Unitary responses of the caudate nucleus to stimulation of various parts of it were investigated by extracellular recording. Latent periods of response discharges varied from 3.5 to 40 msec. Most neurons were excited by stimulation of the most rostral part of the head of the caudate nucleus. Irrespective of the site of stimulation, in most cases responses consisted of initial excitation in the form of one or, less frequently, two discharges followed by a period of depression of spontaneous activity. Recovery of activity took place gradually, without postinhibitory facilitation. No afterdischarges or periodic repetitions of spikes were observed after the initial response. Repetitive stimulation of the caudate nucleus showed that the neurons of this nucleus reproduce frequencies of stimulation badly above 30/sec, and under these circumstances in many cases they continued to discharge on average at a frequency of 5–15/sec. The results are examined from the standpoint of participation of the caudate nucleus in the formation of spindle activity.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 8, No. 5, pp. 497–506, September–October, 1976.     

Response of caudate nucleus neurons to a photic stimulus at various locations on the visual field in the awake cat

The response of caudate nucleus neurons to presentation of photic stimuli located at varying distances from the fovea centralis was investigated in awake cats. Stimulation of different sites on the visual field below the fovea produced dissimilar reactions in 25 of the 35 (or 71%) of these neurons responding to photic stimulation. This divergence of response indicates that in 6 of these cells (or 17%) the receptive fields in the test area of the visual field bordered on the central area of the latter and 6 neurons (17%) showed reduced sensitivity to the effects of stimuli nearer to the periphery than to the center of the visual field, while 13 units (37%) were receiving qualitatively different information from various sites on the field of vision. On the basis of our findings we deduced that caudate nucleus neurons are involved in the analysis of visual sensory signals.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 18, No. 2, pp. 241–250, March–April, 1986.     

Chemical stimulation of the thalamic reticular nucleus inhibits the neuronal activity of the posterior insular cortex in rats

Extracellular neuronal responses were recorded from the posterior insular cortex following electrical and chemical stimulation of the thalamic reticular nucleus (Rt) regions. In the present study, most neurons (29/32) were first characterized for their responses to electrical stimulation of the superior laryngeal (SL) nerve or glossopharyngeal (IXth) nerve. In the first experiment, 15 neurons in the posterior insular cortex were examined for their responses to electrical stimulation of the Rt regions. It was found that effective stimulation sites to evoke action potentials in the posterior insular cortex were the ventromedial portion of the Rt and its adjacent regions. In the second experiment, 17 neurons in the posterior insular cortex were examined for their responses by pressure injection of glutamate (Glu) into the Rt regions. Of the 17 neurons, 13 were inhibited in the spontaneous discharge rate following injection of Glu into the Rt, and the remaining four were unaffected. Histologically, it was demonstrated that Glu injection sites for the case of inhibition were located near or within the Rt. On the other hand, the injection sites for all four non-responsive neurons were located outside of the Rt. These data suggest that excitation of the Rt (GABAergic neurons) causes depression of the neuronal activity in the thalamic relay nucleus and then this may in turn induce depressed neuronal activity in the posterior insular cortex. The results here indicate that neuronal activity in the posterior insular cortex is controlled by the Rt, which has been reported in other sensory systems.     

Comparative neurophysiological characteristics of shivering and caudate tremor

Two models of postural tremor — induced by cold (shivering) and by injection of oxotremorine into the caudate nucleus (caudate tremor) — were compared in experiments on cats. Both models shared the same electromyographic picture of tremor; the frequency of activity of motor units working independently was 4–12 spikes/sec. Both types of tremor were potentiated by cold stimulation of temperature receptors and were inhibited by electrical stimulation of the medial preoptic region of the hypothalamus and by intravenous injection of cholinomimetics. Caudate tremor, unlike shivering, ceased after intravenous injection of scopolamine (an antiparkinsonism drug). On the basis of data on motoneuron function it is concluded that both types of tremor are analogs of physiological postural tremor. The selective inhibitory action of scopolamine on caudate tremor reflects only the mediator organization of structures in the caudate nucleus and cannot therefore serve as the basis for the conclusion that this disturbance of motor activity is a model of pathological postural tremor.O. V. Kuusinen Petrozavodsk State University. Translated from Neirofiziologiya, Vol. 13, No. 3, pp. 257–263, May–June, 1981.     

Neuronal responses evoked in the bulbar respiratory center by stimulation of the anterior ventral and mediodorsal thalamic nuclei

The effects of rhythmical low- and high-frequency stimulation of specific nonsensory anterior ventral and associative mediodorsal thalamic nuclei (AV and MD, respectively) on the activity of neuronal units in the medullary ventral respiratory nucleus were studied in acute experiments on anesthetized, spontaneously breathing cats. Both inhibitory and excitatory influences on spike activity of inspiratory and expiratory neurons were found, with suppression effects being markedly predominant. Thresholds for inspiratory neuronal responses were lower as compared with those for expiratory cells. Electrical AV stimulation mainly produced an inhibitory effect on the activity of nonspecific reticular neurons (without respiratory activity), whereas during MD stimulation activating effects on these neurons dominated. Possible mechanisms underlying the realization of thalamorespiratory influences are discussed.Neirofiziologiya/Neurophysiology, Vol. 25, No. 3, pp. 218–223, May–June, 1993.     

Spectral analysis and mathematical modeling of electrical cerebral activity in rats with genetically determined predisposition to seizure and in controls

Spectral signs of genetically determined predisposition to seizure characteristic of Krushinskii-Molodkina (KM) strain rats were found when studying summated cerebral potentials, namely increased power of low (1–3 Hz) frequencies in spectra of motor and visual cortex potentials together with an abrupt increase and a reduction respectively in the power of hippocampal and caudate nucleus potentials. Comparative spectra of summated electrical activity within neuronal networks [10] and those of experimentally obtained potentials as determined by modeled parameters simulating neuronal networks were found (an inverse problem of modeling). It was found that spectral signs of predisposition to seizure could reflect changes in the physiological properties of neuronal networks belonging to the rat brain structures investigated. It might be suggested on the basis of the calculations performed that genetic predisposition to seizure in KM strain rats is determined by attenuation of the inhibitory function of the caudate nucleus and by heightened excitability (reactivity) in neurons of the paleo- and neocortex.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 2, pp. 184–193, March–April, 1990.     

Convergence and interaction of reticulofugal and peripheral afferent impulses on caudate neurons in the cat

Extracellular investigations on the activity of 269 caudate neurons during electrical stimulation of the midbrain reticular formation were carried out during chronic experiments on cats. Stimuli of different sensory modalities were used: auditory, mechanical, and visual. A response was observed to both reticular and peripheral stimulation in single neurons. The former produced an orthodromic response in 53% of caudate neurons, notable for its high probability of occurrence. A total of 23% of caudal neurons responded to this type of stimulation and application of stimuli of a single modality, while 14% responded polymodally. An excitatory response pattern prevailed during all types of stimulation. By applying twin stimuli to 100 caudate neurons, a capacity for interaction between reticular and acoustic inputs was discovered. Interaction was similarly observed in neurons which had reacted neither to separate application of both stimuli nor to either of the stimuli in isolation.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 19, No. 1, pp. 101–110, January–February, 1987.     

Neuronal responses of a chronically isolated slab of auditory cortex to intracortical stimulation during paroxysmal electrical activity in cats

Responses of 155 neurons 3 weeks after neuronal isolation of a slab of auditory cortex (area AI) to single intracortical stimulating pulses at the level of layer IV were studied in unanesthetized, curarized cats during paroxysmal electrical activity evoked by series of high-frequency (10–20 Hz) electrical stimulation by a current 2–5 times above threshold for the direct cortical response. In response to such stimulation a discharge of paroxysmal electrical activity, lasting from a few seconds to tens of seconds, appeared in the slab. As a rule it consisted of two phases — tonic and clonic. This indicates that cortical neurons can form both phases of paroxysmal cortical activity. Depending on behavior of the neurons during paroxysmal electrical activity and preservation of their ability to respond to intracortical stimulation at this time, all cells tested in the isolated slab were divided into four groups. Their distribution layer by layer and by duration of latent periods was studied. Two-thirds of the neurons tested were shown to generate spike activity during paroxysmal discharges whereas the rest exhibited no such activity. A special role of neurons in layer II in generation of paroxysmal activity in the isolated slab was noted. The view is expressed that at each moment functional neuronal circuits, independent of each other, exist in the slab and also, evidently in the intact cortex, which can interact with one another when conditions change.I. I. Mechnikov Odessa State University. Translated from Neirofiziologiya, Vol. 16, No. 1, pp. 3–11, January–February, 1984.     

Single unit responses of the reticular and ventral anterior nuclei of the thalamus to electrical stimulation of the centrum medianum

In acute experiments on cats anesthetized with thiopental (30–40 mg/kg, intraperitoneally) and immobilized with D-tubocurarine (1 mg/kg) responses of 145 neurons of the reticular and 158 neurons of the ventral anterior nuclei of the thalamus to electrical stimulation of the centrum medianum were investigated. An antidromic action potential appeared after a latent period of 0.3–2.0 msec in 4.1% of cells of the reticular nucleus and 4.4% of neurons of the ventral anterior nucleus tested in response to stimulation. The conduction velocity of antidromic excitation along axons of these neurons was 1.7–7.6 m/sec. Neurons responding with an antidromic action potential to stimulation both of the centrum medianum and of other formations were discovered, electrophysiological evidence of the ramification of such an axon. Altogether 53.8% of neurons of the reticular nucleus and 46.9% of neurons of the ventral anterior nucleus responded to stimulation of the centrum medianum by orthodromic excitation. Among neurons excited orthodromically two groups of cells were distinguished: The first group generated a discharge consisting of 6–12 action potentials with a frequency of 130–640 Hz (the duration of discharge did not exceed 60 msec), whereas the second responded with a single action potential. Inhibitory responses were observed in only 0.7% of neurons of the reticular nucleus and 4.4% of the ventral anterior nucleus tested. Afferent influences from the relay nuclei of the thalamus, lateral posterior nucleus, and motor cortex were shown to converge on neurons responding to stimulation of the centrum medianum.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 36–45, January–February, 1980.     

Response of caudate nucleus neurons to acoustic stimulation during functional blockade of the thalamic centrum medianum in the cat

The response of caudate nucleus neurons to acoustic stimulation (a click at 0.5 Hz) was investigated during chronic experimentation in cats using intracellular techniques and reversible blockage of the thalamic centrum medianum produced by anode polarization. Having analyzed poststimulus histograms it was found that the response of phasic activation to an acoustic signal decreased, and disappeared in 52% of neurons. A reduction in the level of spontaneous activity was also observed in neurons of the caudate nucleus. The significance of a direct pathway from the thalamic centrum medianum to the caudate nucleus is discussed from the viewpoint of acoustic signal transmission to caudate nucleus neurons.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 18, No. 1, pp. 92–99, January–February, 1986.     

Neuronal responses of the reticular and anterior ventral thalamic nuclei to stimulation of the thalamic ventrolateral nucleus and motor cortex

Responses of 137 neurons of the rostral pole of the reticular and anterior ventral thalamic nuclei to electrical stimulation of the ventrolateral nucleus and motor cortex were studied in 17 cats immobilized with D-tubocurarine. The number of neurons responding antidromically to stimulation of the ventrolateral nucleus was 10.5% of all cells tested (latent period of response 0.7–3.0 msec), whereas to stimulation of the motor cortex it was 11.0% (latent period of response 0.4–4.0 msec). Neurons with a dividing axon, one branch of which terminated in the thalamic ventrolateral nuclei, the other in the motor cortex, were found. Orthodromic excitation was observed in 78.9% of neurons tested during stimulation of the ventrolateral nucleus and in 52.5% of neurons during stimulation of the motor cortex. Altogether 55.6% of cells responded to stimulation of the ventrolateral nucleus with a discharge of 3 to 20 action potentials with a frequency of 130–350 Hz. Similar discharges in response to stimulation of the motor cortex were observed in 30.5% of neurons tested. An inhibitory response was recorded in only 6.8% of cells. Convergence of influences from the thalamic ventrolateral nucleus and motor cortex was observed in 55.7% of neurons. The corticofugal influence of the motor cortex on responses arising in these cells to testing stimulation of the ventrolateral nucleus could be either inhibitory or facilitatory.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 10, No. 5, pp. 460–468, September–October, 1978.     

Study of neuronal organization of the “gastric” region in the dorsal motor nucleus of the vagus nerve

The peculiarities of neuronal electrical activity in the dorsal motor nucleus (0.5–2.0 mm rostrally to the obex) were investigated in acute experiments on cats, using the microelectrode technique, under conditions of stimulation of the gastric vagal branches. In the gastric region of the nucleus, two groups of cells responding to nerve stimulation were identified: preganglionic parasympathetic neurons antidromically activated by such stimulation, and cells excited orthodromically with the involvement of afferent fibers of the vagus nerve.Neirofiziologiya/Neurophysiology, Vol. 25, No. 3, pp. 190–196, May-June, 1993.     

Various forms of potentials recorded from caudate nucleus neurons

Spontaneous and evoked activity of caudate nucleus neurons was recorded extracellularly in acute experiments on cats. Different forms of potentials were found by analysis of the results. The potentials recorded belong to three types: ordinary action potentials; prepotentials or incomplete spikes differing from ordinary action potentials in their lower amplitude and slower decline, and complex discharges in which a spike of somewhat reduced amplitude is followed by a slow positive-negative wave. In the spontaneous activity prepotentials were observed both in complete action potentials and in isolation. The frequency of the complex discharges was 0.5–1 per second. The slow wave of these discharges blocked prepotential and action potential formation. The origin of these forms of potentials in neurons of the caudate nucleus is discussed and they are compared with analogous forms of potentials described for the Purkinje cells of the cerebellum.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukranian SSR, Kiev. Translated from Neirofiziologiya, Vol. 9, No. 2, pp. 149–156, March–April, 1977.     

Electrophysiological investigation of effect of pulvinar stimulation of caudate nucleus neurons that react to visual stimulation

Responses of caudate neurons to electrical stimulation of the afferent input from thepulvinar thalamic nucleus and to visual stimuli of various orientations were studied extracellularly in awake chronic cats. Activation responses dominated among reactions of these neurons. The response latencies have ranged from 4 to 85 msec for units with primary activation and from 20 to 150 msec for inhibited ones. The values are indicative of both rapidly and slowly conducting afferent pathways. A possibility of monosynaptic transmission in thepulvinarcaudate projections is also revealed.Pulvinar stimulation is found to be efficient for a significant (more than 50 percent) number of caudate neurons responding to visual stimuli, including orientation-selective cells. The mode of influences from other structures of the visual system (optic tract, area 17, the Clare-Bishop area) on caudate neurons responding topulvinar stimulation is described. The data are discussed with respect to the possible role of cortical and subcortical projections of the visual system in the creation of sensory specific responses of the caudate nucleus.A. A. Bogomolets Physiology Institute, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 23, No. 5, pp. 520–529, September–October, 1991.     

Response of cat auditory cortex neurons to tonal stimulation during and after nembutal anesthesia

During acute experiments on 20 cats a comparative study was made of neuronal reaction to a tone, as recorded during the first few hours after administration of Nembutal and after an interval of 10–30 h. No spontaneous activity was seen in 89% of auditory cortex neurons of the anesthetized cats; these produced a sterotyped on- response to the optimal frequency tone. Late neuronal spike discharges at distinct intervals of 100–150 msec appeared in response to the setting up of acoustic stimulation after a brief latent reaction lasting 9–15 msec. It was shown that this stimulation did not produce an off-response in the cortical neurons. When the animals emerged from Nembutal anesthesia, the neurons reacted very differently to the optimal frequency tone. About 76% of the cells produced an on, on-off or off response, while about 21% responded with either tonic spike discharges or total inhibition of these throughout the acoustic stimulation. In unanesthetized cats the vast majority of AI cortical neurons were capable of reacting as long as the stimulus lasted. It is shown how this ability is lost under deep Nembutal anesthetic.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 17, No. 6, pp. 728–737, November–December, 1985.     

Changes in Nine Enzyme Markers for Neurons, Glia, and Endothelial Cells in Agonal State and Huntington''s Disease Caudate Nucleus

Enzymes considered to be markers for neurons (angiotensin converting enzyme, thermolysin-like metalloendopeptidase, alanine aminopeptidase, and glutamate-oxaloacetate transaminase), glia (glutamine synthetase, pyruvate carboxylase, and beta-glucuronidase), and endothelial cells (alkaline phosphatase and plasminogen activator) were measured in caudate nucleus from 10 sudden death controls, eight agonal state controls, and 16 Huntington's disease patients. Glutamate-oxaloacetate transaminase was slightly reduced by agonal state. The four enzymes with a neuronal distribution were all correlatively reduced in Huntington's disease caudate nucleus. Glutamine synthetase activity was reduced and beta-glucuronidase mean activity increased over twofold in Huntington's disease caudate nucleus, with the two enzyme activities being inversely related. Pyruvate carboxylase was markedly affected by agonal state and was very variable in Huntington's disease caudate nucleus. The two endothelial enzymes were unaltered in Huntington's disease caudate nucleus. The findings are indicative of neuronal loss, an increased proportion of altered glia, and also of maintained vasculature in Huntington's disease caudate nucleus. Measurement of enzyme activities can help to delineate the types of cell altered in Huntington's disease.