PubMed Health⌕ Search

Biomedical subjects

M I Zaĭchenko

Publications and source records attributed to M I Zaĭchenko.

16 recordsLinked to original sources
PubMedDate not supplied

[Neuronal activity in the prefrontal cortex in rats with various typological features during emotional affect].

Unit activity in the right and left prefrontal cortex was recorded in male Wistar rats after testing by the emotional resonance technique. Rats were divided in two groups by their reaction to the suffering cry of a partner. Rats from the group A ("altruists") escaped partner's crying, and those from the group E ("egoists") did not. Activity of neurons was analyzed in hungry rats, after feeding, during intracranial emotionally positive and negative stimulation, and during crying of the rat partner. Some differences in neural activity between A and E groups were revealed. In the hungry state the rate of neuronal discharges was higher in the A group. In both groups of animals the positive emotional stimulation was accompanied by more intensive neuronal reaction that the negative stimulation, but in the E group increase in the rate of neuronal discharges in both hemispheres was significantly more pronounced. Negative stimulation produced in both groups a significantly greater activation in the left hemisphere than in the right one while during the positive stimulation the neural activity was more intensive in the left hemisphere. The neuronal reaction to partner's crying was significantly higher in the A group in both hemispheres, while the neuronal activity in E group did not significantly change.

Animals↗
PubMedDate not supplied

[Interhemispheric relations of prefrontal cortical neurons in rats during emotional stimulation of increasing intensity].

Unit activity of the prefrontal cortex of the right and left brain hemispheres of rats was recorded during intracranial stimulation of emotionally positive and negative brain structures. The neurons were divided according to their reaction to a change in food motivation: cells that decrease (M-neurons) and cells that increase their firing frequencies (R-neurons) after feeding. Three levels of stimulation current intensity were used. When stimuli of subthreshold intensity (evoking the behavioral reaction of smelling) were applied, the recorded neuronal activity was higher in the left hemisphere. During threshold emotionally positive or negative stimulation (producing approach behavior or freezing, respectively), activity of M-neurons was higher in the right hemisphere, whereas the left-side R-neurons were more active than the right-side ones. During strong emotionally positive stimulation producing self-stimulation, the firing frequency of both groups of neurons was higher in the left hemisphere. Strong emotionally negative stimulation that evoked behavioral avoidance to a greater extent activated the right hemisphere.

Animals↗
PubMedDate not supplied

[Interhemispheric asymmetry in the functional organization of the prefrontal cortex in animals of different typologic groups].

Rats allocated to groups by the method of "emotional resonance": rats which did and did not escape crying of a partner (A- and E-groups, respectively). Unit activity in the right and left prefrontal brain cortex (PFC) was recorded in these rats. The recorded neurons neurons were divided in two groups according to their reaction to a change in the level of food motivation. The so-called D-neurons decreased their activity after feeding of animals after a 24-hour food deprivation and the other group (I-neurons) increased its firing rate rate in this situation. It was shown that hemispheric distributions of D- and I-neurons are different in selected rat groups. In E-rats the I-neurons substantially predominated in the left hemisphere, whereas the D-neurons were more frequently recorded in the right one. No such asymmetry was observed in A-group of rats. During intracranial stimulation of emotionally positive brain structures I-neurons increased their firing rate, predominantly, in the left hemisphere, whereas during intracranial emotionally negative stimulation activation of the D-neurons predominated at the right. Features of the observed functional interhemispheric asymmetry of prefrontal cortex in A- and E-groups of rats were explained by differences in the interaction between hemispheres and dissimilar activation control.

Animals↗
PubMedDate not supplied

[Hippocampal neurons of the CA3 field in animals of different typological groups exposed to emotional stimuli].

Hippocampal unit activity in of the right and left CA3 fields was studied in rats which were divided in two groups by the method of "emotional resonance": the animals that did ("A") and did not stop ("E") crying of rat-partner. The rate of neuron firing was studied in the state of hunger, satiation, and under exposure to intracranial electrical stimulation of the emotional positive and negative structures of the brain. It was shown that the intracranial stimulation, especially positive, increased the rate of firing. Under exposure to emotional stimuli, the neural activity was asymmetric only in E rats. The activity at the left was more intensive then the right-side activity and did not depend on the sigh of emotion.

Animals↗
PubMedDate not supplied

[Effect of dalargin on the processes of memory and learning in the rat].

In experiments on rats, the influence was studied of dalargin on the elaboration and preservation of various homogeneous and heterogeneous conditioned reflexes (CRs) elaborated in single and multiple pairings. The effect of dalargin on the processes of learning and memory was compared with the action of the peptide on the activity of hypothalamic neurones. Administration of dalargin delayed the elaboration of maze defensive CRs and practically did not affect the elaboration of two-way avoidance. The preservation of CR also deteriorated under the influence of dalargin. Administration of dalargin 10 min before the CRs testing did not prevent their reproduction. When using CRs elaborated in a single pairing, dalargin disturbed the preservation of the drinking CR and improved that of passive avoidance CR. Dalargin in this dose affected the emotional state of animals in the open field and did not significantly affect their motor activity. Dalargin suppressed impulse activity in 17 out of 22 tested neurones of the lateral hypothalamus, with maximum effect in 20-50 min after its administration. The obtained data show that the character of dalargin action on the elaboration of CR and mainly on its consolidation, depends on the character of the elaborated CR and is probably due to great extent to the effect of the peptide on the brain emotional mechanisms.

Animals↗
PubMedDate not supplied

[The neuronal reactions of the emotional areas of the hippocampus in emotional exposures of different characters].

Reaction of neurons of the emotiogenous hypothalamic regions (lateral hypothalamic area (LH), hypothalamic preoptic area (HPA), ventromedial hypothalamus (VMH)) to intracranial and peripheral emotionally positive and negative stimuli were studied in rats. These responses were compared with alteration of unit activity after feeding the food-deprived animals. Some neurons responded in the same way to all the stimuli applied (non-specific reaction). Neurons with the opposite (specific) reactions to positive and negative emotional stimuli represented 21% of recorded neurons in LH, 23% of those in HPA, and 30% in VMH. Hypothalamic neurons with non-specific and specific types of reactions seem to be the elements of different activation systems. The first of them are related to non-specific activation which determines arousal level and the second ones are involved in specific, local activation which participates in the regulation of a number of types of behaviour.

Animals↗
PubMedDate not supplied

[Hypothalamic neurons and defensive reflexes].

Identified groups of neurons in positive (the lateral hypothalamic area, the lateral preoptic area) and negative (the ventromedial hypothalamus) emotional regions were examined under the different levels of food motivation and emotionally positive and negative intracranial stimulation. The responses of the neurons in classical and operant conditioning were different. This difference was manifested in tonic (during location of the animal into the chamber) and phasic alterations of neuronal activity and at certain stages of conditioned reflex performance. During classical conditioning were revealed the reciprocal relations in unit activity of the positive and negative emotional structures. During the operant reflex more complicated pattern of reactions was observed being connected with realization of a necessity of removing from the negative influences. During defensive reflex in the cases of classical conditioning and avoidance reaction reinforcement was related with engaging the negative emotional mechanisms while in the course of escape reaction the positive emotional mechanism being engaged.

Animals↗
PubMedDate not supplied

[The characteristics of the coordinated activity of functionally identified hypothalamic neurons under different motivational-emotional states].

Simultaneous impulse activity of pairs of neurons in hypothalamus was analysed in different natural functional states of rats (hunger, satiation after food deprivation, cry of a victim) and those induced by electrical stimulation of the emotionally positive (lateral hypothalamus, lateral preoptic area) and negative (dorso-medial tegmentum) reinforcing hypothalamic structures. Two classes of neurons were separated according to the pattern of their activity determined by the motivational state or reinforcement. Characteristic features were revealed in the patterns of conjugate activity of the functionally identified neurons. They were determined by the dominance of motivational or emotional component in the behaviour of an animal and manifested in a specificity of temporal delays in impulsation of one of the neurons in respect to the other one, in magnitude and number of positive and negative correlations. The results suggest the different ways of realization of the motivational and reinforcing hypothalamic influences mediated by the neurons of the motivational and reinforcing systems, on the cortical processes at different stages of learning which also differ in the balance between the motivational and emotional components of the animal behaviour.

Animals↗
PubMedDate not supplied

[Hypothalamic neurons and zoosocial interactions].

Unit activity in the lateral hypothalamic area was recorded in rats after testing by the emotional resonance technique. The rats were divided in two groups by their reaction to the suffering cry of the partner ("victim"). Rats from the group I ("altruists") escaped ("victim") crying, and those from the group II ("egoists") did not. Activity of neurons was analysed in hungry rats, after feeding, after placing the "victim" into the experimental chamber, during intracranial emotionally positive and negative stimulation, and during crying of the "victim". The results showed that the majority of neurons of the rats from the I group responded to the partner's crying in the same way as to the intracranial emotionally negative stimulation and the reaction of the neurons of the rats from the II group was either poorly expressed or resembled that to the intracranial emotionally positive stimulation.

Animals↗
PubMedDate not supplied

[The neurons of the right and left prefrontal areas of the rat cerebral cortex and the stimulation of emotiogenic zones].

The effect of emotions on unit activity of the prefrontal cortex (right and left hemispheres) was studied in rats under conditions of stimulation of emotionally positive (lateral hypothalamic area) and negative (dorsomedial tegmentum) structures. The stimulation produced changes in unit activity of both the right and left hemispheres. Asymmetry was revealed in neuronal responses of the right and left areas of the prefrontal cortex: during emotionally positive stimulation the unit activity in the left cortex was more intensive, and the neurons of the right cortex were more active during the negative stimulation. In case of the negative emotional stimulation the greater asymmetry in neuronal responses was observed at contralateral stimulation, at the positive stimulation both the left and right localizations were equally effective.

Animals↗