[The bioelectrical activity of the brain in an organic lesion of the central nervous system presenting in those who worked in the cleanup of the aftermath of the accident at Chernobyl Atomic Electric Power Station]. / Bioélektricheskaia aktivnost' golovnogo mozga s organicheskim porazheniem tsentral'noi nervnoi sistemy, voznikshim u likvidatorov posledstvii avarii na ChAES.

A study was made of brain bioelectric activity in 122 patients who developed organic lesions of the brain following their taking part in the elimination of the effects of Chernobyl disaster. A visual analysis was performed as was an assessment of the electroencephalogrammes (EEG) obtained, as recommended by E. A. Zhirmunskaia. Disorganization of bioelectrical activity occurred in organic lesions of the brain in 26.5% of cases, which fact suggested disturbances in the activity of control systems of the brain. Disorganized EEG with marked disturbances in both cortical and regulatory electrogenesis were common in patients presenting with psycho-organic syndrome. The results obtained will, we believe, help in elucidating one of the links in the pathogenesis of the above conditions and selecting a complex of adequate therapeutic measures to be instituted in his pathology treatment setting.

[Interaction of effects of functionally different zones of the cerebral cortex on the caudate nucleus neurons in the cat]. / Vzaimodeistvie vliianii funktsional'no razlichnykh zon kory golovnogo mozga na neironakh khvostatogo i adra koshki.

Extracellular recording from the caudate nucleus neurons was performed in experiments on immobilized cats during paired stimulation of anterior sigmoideus and middle suprasylvius gyri. The findings indicate that the two cortical areas influence these neurons, the motor cortex having a greater influence on caudate neurons than the association cortex. The same interaction was recorded after a deep transcortical dissection between the stimulated areas.

[Reactions of cat caudate nucleus neurons to cortical stimulation before and after destruction of nonspecific thalamic nuclei]. / Reaktsii neironov khvostatogo iadra koshek na razdrazhenie kory do i posle razrusheniia nespetsificheskikh iader talamusa.

In experiments on immobilized cats extracellular responses of caudate nucleus neurons were recorded during electrical stimulation of anterior sigmoideus and suprasylvius gyri. In the first set of experiments performed on cats with an intact thalamus the responses to stimulation of both cortical areas represented initial excitation (sometimes absent) followed by inhibition and late activation. Some qualitative and quantitative differences in the neuronal responses to stimulation of these cortical areas were found. The second set of experiments was performed on cats with preliminary destroyed unspecific thalamic nuclei. Changes were observed only in time course of late caudate neuronal responses.

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.

[Analysis of the spike activity of pairs of caudate nucleus neurons in cats]. / Analiz impul'snoi aktivnosti par neironov khvostatogo iadra koshki.

Spike activity of pairs of neurons was recorded simultaneously with a single microelectrode in the caudate nucleus of lightly anaesthetized immobilized cats. A high time correlation was observed in discharges of two neurons when their background activity showed group discharges. In case of unitary background activity, correlation between spike trains was observed only in 50% of the cells; it could be both of excitatory and inhibitory type. Many neuronal pairs exhibited negative short latency correlation in the 0--4 ms range. Electrical stimulation of different afferent inputs of the caudate nucleus caused minimal correlation between neuronal discharges and, on the contrary, abolished correlation between spontaneous discharges of the same pair of neurons. The presented results are discussed from the point of view of the caudate nucleus as an associative cerebral nucleus.

[Analysis of the background activity of cat caudate nucleus neurons]. / Analiz fonovoi aktivnosti neironov khvostatogo iadra koshki.

Background activity recorded extracellularly from the caudate nucleus neurons was analyzed in immobilized cats. Experimental data processing included the plotting of average frequency curves, interspike interval histograms, intensity functions, correlograms and association histograms. The frequency of the background activity in different caudate neurons varied from 0.5 to 20 imp/s and could change in the same neuron in different time intervals. According to the time structure and statistical parameters the background activity of the caudate neurons was classified in two types: unitary and group. Transformation from one type to the other could be observed in the same neuron. The obtained data do not allow considering the background activity of the caudate neurons as simple random pulse trains.

[Different forms of potentials discharged by caudate nucleus neurons]. / Razlichnye formy potentsialov, otvodimykh ot neironov khvostatogo iadra

Background and evoked activities of the caudate neurons were recorded extracellularly in acute experiments on cats. Different forms of potentials were observed in background and evoked activity. They could be divided into three types: (a) simple full size action potentials; (b) prepotentials characterized by smaller amplitudes and slower decrement; (c) complex discharges consisting of simple potentials of smaller amplitude accompanied by slow positive-negative waves. Prepotentials were observed in background activity separately or as components of full size spikes. Frequency range of complex discharges was 0.5-1 per s. Prepotentials and full size potentials were arrested by slow waves of the complex discharges. The observations are discussed with regard to the origin of diverse forms of the potentials in the caudate nucleus neurons and compared to those made on the cerebellar Purkinje cells.

[Reaction of caudate nucleus neurons to direct stimulation]. / Reaktsii neironov khvostatogo iadra na ego priamuiu stimuliatsiiu

Extracellular recording from the caudate nucleus neurons were performed in experiments on immobilized cats during electrical stimulation of different parts of the same nucleus. Latencies varied from 3.5 to 40 msec. Most neurons could be excited by stimulation of the most rostral part of the caudate nucleus head. In most cases responses were independent of the stimulation place. The responses consisted of one or rarely two spike followed by inhibition of background activity. Then activity gradually restored without rebound. Afterdischarges were not observed. The caudate neurons hardly reproduced stimulating frequencies more than 30 per second and retained in most cases their own frequency level (on the average 5-15 spikes/sec.). The results are discussed in connection with participation of the caudate nucleus in the origin of spindle activity.