[Pathways of visual and auditory information transmission in the caudate nucleus of the cat]. / Puti peredachi zritel'noi i slukhovoi informatsii v khvostatoe iadro koshki.

Visual and auditory projections to the caudate nucleus were studied in cat by combination of the HPR method and experimental degeneration of retinal axons. It was shown that visual information comes to the caudate nucleus not only through the well-known polysynaptic pathways from the cerebral cortex, but also through both oligosynaptic (via pulvinar, lateroposterior nucleus, suprageniculate nucleus and nucleus limitans of the thalamus) and disynaptic pathways (via medial and lateral terminal nuclei of the accessory optic tract, pulvinar, pretectum, intermediate superior colliculus layer, supraoptic nucleus) some of which were found for the first time. Direct retinal inputs to the suprageniculate nucleus were found. Additional sources of auditory information to the caudate nucleus were revealed being as follows: the dorsal nucleus of parvocellular division of the medial geniculate nucleus, deep superior colliculus layer, dorsal and ventral nuclei of the lateral lemniscus. Physiological significance of the revealed pathways for the possible transmission of visual and auditory impulses and a new principle of organization of sensory inputs to the caudate nucleus are discussed.

[Rhythmic background activity of the thalamic neurons of patients with extrapyramidal movement disorders]. / Ritmicheskaia fonovaia aktivnost' talamicheskikh neironov u bol'nykh s ékstrapiramidnymi dvigatel'nymi narusheniiami.

When applying the microelectrode method in neurosurgical clinic to differentiate white matter and thalamic nuclei the background activity of 123 thalamic neurons has been registered in 30 patients with motor extrapyramidal disorders. The recordings were performed from ventral oral anterior, ventral oral posterior and adjacent reticular thalamic nuclei. Autocorrelation functions and spectral density functions for the activity of 44 cells were analyzed. In patients with parkinsonism and double athetosis a number of cells (48%) with rhythmic activity were revealed. Regular fluctuations of background neuronal discharges with different frequencies were observed: in the range of thetha-rhythm (5-7 Hz), deltha-rhythm (1-4 Hz), with second (2-10 s) and decasecond (15-40 s) periods. The possibility of simultaneous presence of several regular periodic processes was established: in 8 neurons 2 or 3 waves of acceleration and slowing down of spike discharges have occurred. The question is discussed about the origin and the significance of rhythmic fluctuations of thalamic neuronal discharges.

[Projections of the neurons of the medial terminal nucleus of the accessory optic tract to the caudate nucleus of the cat detected by the combined methods of retrograde axonal transport and experimental degeneration]. / Proektsii neironov medial'nogo terminal'nogo iadra dobavochnogo opticheskogo trakta k khvostatomu iadru u koshki, vyiavliaemye pri sochetanii metodov retrogradnogo aksonnogo transporta i éksperimental'noi degeneratsii.

Projections of neurons of the medial terminal nucleus of the accessory optic tract receiving direct retinal inputs to the head and body of caudate nucleus are shown in cat by the retrograde axonal transport of horseradish peroxidase and experimental degeneration. These projections are mainly ipsilateral and uniformly distributed in the above mentioned parts of the nucleus. The neurons of the medial terminal nucleus establishing synaptic connections with caudate neurons have different shapes and sizes (from 20 X 10 microns to 37.5 X 18 microns) and are located both in the ventral and dorsal parts of the nucleus. Conclusions are made about functional significance of these projections in the regulation of the muscular tension.

[Reactions of neostriatal neurons to direct electric stimulation of the optic tract and to photic stimulation in the alert cat]. / Reaktsii neironov neostriatuma na priamoe élektricheskoe razdrazhenie opticheskogo trakta i na svetovuiu stimuliatsiiu u bodrstvuiushchikh koshek.

Responses of 98 cells in the head and body of caudate nucleus to direct electric stimulation of the optic tract and to visual stimuli were recorded extracellularly in awake chronic cats. 34.6 and 36.2% of the studied cells, respectively, have responded to these types of stimulation. Long-latency (over 40 ms for optic tract and over 80 ms for visual stimulations) excitatory responses prevailed in both cases. Small number of units responded to optic tract stimulation with short (5-14 ms) latencies. Eight of 58 tested cells were activated by both electric and visual stimuli. In this case, responses of the same cells could differ (relatively to the type of applied stimulus) either in pattern or sign. These data are discussed relative to the possible pathways for transfer of the visual information to non-specific brain structures.

[Short-latency responses of neurons of the striate system of the brain to sensory activation]. / Korotkolatentnye otvety neironov striatnoi sistemy mozga koshki na sensornuiu aktivatsiiu.

Experiments were carried out on awake cats to study responses of caudate neurons to different afferent stimuli (visual, auditory, somatic and direct electrical stimulation of medial geniculate body). Mean response latencies varied within 15-55 ms with the maximum value to 200 ms. At the same time 1-10% of cells responded with short latency to all applied stimuli. Significance of short-latency sensory responses in comprehension of principles of sensory processing in non-specific subcortical structures is discussed.

Rhythmic activity of the brain evoked by local injections of carbachol into subcortical nuclei.

The effect of local injections of carbachol into the caudate nucleus and individual nuclei of the thalamus on the electrocorticogram of the anterior portion of the brain was investigated in unanesthetized, immobilized cats. It was shown that chemical stimulation of subcortical structures, like electrical stimulation, can induce spindle-like activity and a recruitment response. The appearance of these reactions after injections of carbachol both into the caudate nucleus and into individual nuclei of the thalamus indicates the existence of a functionally unified caudate-thalamic cholinoreceptive system, responsible for the slow wave rhythmic activity.

[Activity of caudate nucleus neurons during purposeful and forced limb movements in the alert cat]. / Aktivnost' neironov khvostatogo iadra pri tselenapravlennom i naviazannom dvizhenii konechnosti u bodrstvuiushchikh koshek.

Experiments were carried out on freely moving cats in a screened chamber. Activity of 121 neurones of the caudate nucleus head was examined during various sensory stimulations and during realization of components of a behavioural act (natural food-procuring reflex). No prevailing was found of neuronal reactions to impulses from passively contracting muscle groups of the body and the limbs over responses of the same neurones to sensory stimuli or limb movements during food-procuring reflex. A part of the caudate neurones manifested selective reactions. Three neurones reacted only to the opening of the door of the feeding trough, eight neurones changed their activity only during eating, and seventeen neurones reacted only to goal-directed limb movement. Participation of the neostriatum in sensorimotor integration is discussed.

[Sensory properties of neurons of a nonspecific brain structure--the caudate nucleus]. / Sensornye svoistva neironov nespetsificheskoi struktury mozga--khvostatogo iadra.

The paper deals with sensory function of single neurons in nonspecific high-level brain structures. Certain aspects of the problem are shown to be complex and disputable. The choice of the research object, nucleus caudatus, is substantiated. Results of experiments with alert cats are presented. Extracellularly recorded neuronal responses to various light stimuli are compared. Local light stimuli, especially under a definite spatial distribution of illuminated sites in the visual field, are found to be more advantageous in neuron activation than diffuse light. Difficulties in interpretation of the data obtained are discussed in connection with fluctuation of background activity and recorded responses under multiple application of the stimuli. An attempt is made to relate sensory properties of the neostriatum to the regulatory efferent function of this structure.

[Responses of caudate nucleus neurons to different visual stimuli in the actively awake cat]. / Reaktsii neironov khvostatogo iadra na razlichnuiu zritel'nuiu stimuliatsiiu u aktivno bodrstvuiushchikh koshek.

The responses of caudate neurons to diffuse or local (a slit) light stimuli were studied extracellularly in alert cats during natural fixation of the gaze. The number of neurons responding to local light stimulation was much higher than that responding to diffuse light. Local light stimulation produced more extensive inhibition of neuronal activity as well as "off" responses. Some neurons responded selectively to the orientation of slits. All neuronal responses were recorded with latencies of 40-90 ms. The participation of the caudate nucleus in the analysis of visual sensory information is discussed.

[Divergence of axon collaterals of substantia nigra neurons in the forebrain of the rat: double labeling with fluorochromes and horseradish peroxidase]. / Divergentsiia aksonnykh kollateralei neironov chernoi substantsii v perednem mozge krysy: dvoinoe mechenie fliuorokhromami i peroksidazoi khrena.

The origin of divergent and non-divergent pathways from substantia nigra to the thalamus were studied in experiments on rats using retrograde axonal transport of luminescent tracers and horse-radish peroxidase. Two efferent projection systems are shown: the first--with divergence of axon collaterals to the caudato-putamen of both hemispheres, caudato-putamen and globus pallidus, caudato-putamen and nucleus accumbens, ipsilaterally; the second system is directed to the thalamus, and does not form axon collaterals to striatal structures.

[Study of the response of caudate nucleus neurons to direct electric stimulation of the medial geniculate body in the cat]. / Issledovanie reaktsii neironov khvostatogo iadra na priamoe élektricheskoe razdrazhenie medial'nogo kolenchatogo tela u koshki.

Extracellular activity of 124 caudate nucleus neurons during stimulation of parvo- and magnocellular parts of the medial geniculate body by rectangular electrical stimuli were investigated in chronic experiments on cats. Reactions were observed in 54 neurons (43%). Main types of responses were: phasic activation in the form of a single spike or spike discharge, initial activation followed by inhibition and pure inhibition. Excitatory responses prevailed (81% of the reacting neurons). The latent periods in different units fluctuated from 2.7 to 64 ms. In the same unit the latent periods were also very variable, which permits considering them as orthodromic. The mode of the histogram of the latent periods of the excitatory responses was in the range of 9-12 ms. The latent periods of the inhibitory responses varied from 12 to 130 ms and were in most neurons in a range of 40-60 ms. The increase in stimulus intensity led to an increase in response regularity, an increase in the number of spikes, reduced latent periods. In the same neuron the character and the structure of responses to stimulation of the relay nucleus and to sound clicks were usually identical. The latent period of responses to clicks was larger. Peculiarities of functional connection of the medial geniculate body with the caudate nucleus as a forebrain polymodal unspecific structure are discussed.

[Afferent connections of the caudate nucleus of cats studied using the technic of retrograde axonal transport]. / Afferentnye sviazi khvostatogo iadra koshki, issledovannye s pomoshch'iu metoda retrogradnogo aksonnogo transporta.

The horseradish peroxidase method was used to investigate the sources of direct and indirect connections to the caudate nucleus in the cat. It is shown that different cortical and subcortical areas contain cells projecting to the caudate nucleus. Labelled neurons after caudate injections were also found in the globus pallidus. Along with the intralaminar complex the ventral anterior and mediodorsal nuclei were found to be the most significant sources of thalamo-caudate projections. The most caudal projection to the caudate nucleus in the cat was demonstrated by finding labelled neurons in the locus coeruleus. The functional significance of the investigated afferent connections of the caudate nucleus is discussed.