Simultaneous recording of eeg and direct current (DC) potential makes it possible to assess functional and metabolic state of nervous tissue

It has been proposed to assess functional and metabolic state of the brain nervous tissue in terms of bioelectrical parameters. Simultaneous recording of the DC potential level and total slow electrical activity of the nervous tissue was performed in the object of study by nonpolarizable Ag/AgCl electrodes with a DC amplifier. The functional and metabolic state of the brain was determined in terms of enhancement or reduction in the total slow electrical activity and positive or negative shifts in the DC potential level.

Changes in the steady-state potential in rats with focal cerebral ischemia receiving cyclopentyladenosine

Brain function and neuroprotective activity of cyclopentyladenosine in rats with focal cerebral ischemia were evaluated by recording the steady-state potential. Cerebral ischemia was modeled by intravasal occlusion of the left internal carotid and middle cerebral arteries and bilateral occlusion of the common carotid arteries. Recording of the steady-state brain potential during experimental ischemia allowed identifying the development of ischemic depolarization by a negative potential shift. Changes in the steady-state potential after cyclopentyladenosine administration reflected delayed development of ischemic depolarization in the nervous tissue. Cyclopentyladenosine holds much promise for the protection of nerve cells from ischemic injury.

Approach to the study of neurophysiological mechanism of food motivation

The present article estimates depolarization-polarization processes in the nerve tissue of afferent systems, including visceral ones, according to the changes of the direct current (DC) potential level. Food motivation is formed and satisfied concurrently with changes in the neocortex direct current potential level and a number of cerebral brain limbic structures in rats. Lateral hypothalamic nucleus, basolateral amygdala area, and auditory cortex in hungry rats have a more negative DC potential shift than in satisfied animals, while a reverse relation is observed in the ventromedial hypothalamic nucleus. The results obtained are considered an indication of polarization shifts in the mechanism of motivated and emotional behavior. An idea of the determining role of polarization processes in the mechanism of motivated and emotional behavior is developed.

[Minimum-invasive model of the rat brain focal ischemia]

The problem of brain ischemia damage treatment stimulates the search for new effective methods, which are studied on various experimental models. Most of such models possess significant disadvantages, producing hypoxia in the whole organism, being poorly controlled, involving serious traumas, and still being far from true pathological mechanisms accompanying the ischemia development. A model of focal brain ischemia in rats, induced by middle cerebral artery intravasal occlusion, is free of these disadvantages.

The relation of emotions to polarization processes in sensory systems

A new concept of the neurophysiological mechanism of emotions is discussed. The emotions are thought to be a state of polarization of neurons involved in processing of emotion generating information. The hypothesis has been supported by an experiment performed to examine the behavior of rats in the "open field" during direct current polarization of visual and auditory cortices. It has been shown that artificial polarization of sensory neurons of the visual cortex but not of the auditory is followed by the appearance of negative emotion in the "open field." The results obtained are discussed in terms of the hypothesis advanced.

[Interhemispheric asymmetry and the typological characteristics of the nervous system in rats]

The paper is devoted to studies of interrelations between behavioural dominance of the left or right hemisphere and typological characteristics of the nervous system in rats. Rats with a strong type of nervous system are shown to possess species-specific interhemispheric asymmetry. In animals with a balanced nervous system it is greater than in animals with an unbalanced nervous system. Rats with a weak type of nervous system have no species-specific interhemispheric asymmetry.

Interhemispheric asymmetry of positive emotional reactions in rats

Interhemispheric asymmetry of positive conditional reactions in rats were investigated, i.e., reactions of drinking need and self-stimulation satisfaction. A successive hemisphere inactivation was performed by potassium spreading depression. Both right and left hemisphere inactivation were shown symmetrically to affect the total quantity of water consumed by the rats until complete thirst satisfaction, i.e., the need magnitude. At different stages of thirst satisfaction, however, interhemispheric asymmetry was observed: when drinking motivation was strong, the right hemisphere dominated, when it was weak the left hemisphere was dominant. Right hemisphere inactivation caused a decrease in the frequency of lateral hypothalamus self-stimulation, whereas with left hemisphere inactivation it increased, which testifies to right hemisphere dominance in self-stimulation reaction. Self-stimulation reaction was also characterized by the asymmetry of lateral hypothalamus nuclei: reactivity of the right nucleus to hemisphere inactivation (decrease or increase in self-stimulation frequency) was more pronounced than that of the left nucleus.

[Interhemispheric asymmetry of positive emotional reactions in rats]

Interhemispheric asymmetry of positive emotional reactions was studied in rats: satisfaction of drinking need and self-stimulation. Successive inactivation of the hemispheres was carried out by potassium spreading depression. Switching off of the right as well as the left hemispheres symmetrically influenced the whole quantity of the water, drunk by the rats to a full thirst satisfaction, i. e. the magnitude of need. However, at different stages of drinking need satisfaction an interhemispheric asymmetry was observed: under a strong drinking motivation the right hemisphere dominated, under a weak motivation--the left one. Switching off of the right hemisphere lowered the frequency of self-stimulation of the lateral hypothalamus and switching off the left one heightened it, testifying to the dominance of the right hemisphere in the reaction of self-stimulation. This reaction was also characterized by asymmetry of the lateral hypothalamus nuclei; reactivity to hemispheres inactivation (decreasing or increasing of self-stimulation frequency) of the right nucleus was more expressed than that of the left one.

Cerebral lateralization of emotional reaction in rats during different emotional pressures

Interhemispheric asymmetry of the "emotional resonance" reaction with a varied degree of emotional action was investigated in rats. Hemisphere inactivation was carried out by means of potassium spreading depression. "Emotional resonance" in rats has been shown to possess hemisphere asymmetry. This asymmetry is dynamic and changes depending upon the conditions under which the reflex is worked out. With equal illumination of both the preferred and the nonpreferred chamber and using "recipients" and "victims" of the same sex, left hemisphere dominance was found in males in carrying out the reaction. With a tenfold difference in chamber illumination and testing animals of the same sex, the right hemisphere dominated in rats working out the reflex quickly, whereas in those working out the reflex more slowly it was the left one. In using "victims" and "recipients" of the opposite sexes and the same darkening of the preferred chamber the right hemisphere dominated in carrying out "emotional resonance." "Emotional resonance" in lactating females to the cry of their pups was also characterized by right hemisphere dominance. Thus, dependence between the force of emotion and the direction of "emotional resonance" lateralization in rats was shown. The interhemispheric asymmetry observed was more expressed in males than in females.

[Interhemispheric asymmetry of "emotional resonance" in the rat]

Hemispheric asymmetry of "emotional resonance" elaborated by the method of P.V. Simonov was studied in Wistar rats. Inactivation of hemispheres was carried out by means of spreading depression. When using as "victims" and "recipients" the animals of the same sex, lateralization of emotional resonance was found to depend upon the velocity of reaction elaboration. In rats rapidly elaborating avoidance reaction the right hemisphere dominated during its performance and so did the left one in animals learning after additional training. When using the animals of different sex as "victims" and "recipients", the right hemisphere dominated in "emotional resonance" performance. Hemispheric asymmetry of "emotional" resonance was more expressed in males than in females.