PubMed Health⌕ Search

Biomedical subjects

E B Filippova

Publications and source records attributed to E B Filippova.

At least 19 recordsLinked to original sources
PubMed1992

[The effect of sex steroid hormones on interhemispheric asymmetry in rats].

The effect of gonadectomy and sex-steroid hormones treatment on functional interhemispheric asymmetry to the reaction of pain cry avoidance of another species (emotional reactions) and motor and exploratory activity of open-field behavior in Wistar rats of 3 months old has been investigated. A spreading depression technique for hemisphere inactivation has been used. The hemispheric asymmetry of the reactions in intact rats was characterized by sex dimorphism; the left hemisphere dominated to a great extent in males than in females under the control of emotional reactions; in motor and exploratory activity in open-field behavior of rats the left hemisphere dominated in males and the right one--in female. In both sexes the neonatal gonadectomy levelled the interhemispheric differences in reactions under investigation. The following treatment of females with estradiol and males with testosterone didn't restore the asymmetry. After the castration at the age of 3 months the correlation between the size and direction of interhemispheric differences became reverse. The treatment of females with testosterone and males with estradiol both castrated in adulthood restored the interhemispheric asymmetry in males and had no effect in females. The treatment of intact rats with hormones of opposite sex led to the enhancement of left hemisphere dominance in motor and exploratory activity in males and levelled the asymmetry in females. It has been shown that in adult rats sex-steroids effect predominantly the right hemisphere.

Aging↗
PubMed1989

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.

Animals↗
PubMed1986

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.

Animals↗
PubMed1985

Hemisphere lateralization of the extrapolation reflex.

The interhemispheric asymmetry of extrapolation task solution in infant and adult Norway rats (Rattus norvegicus) was investigated. L. V. Krushinsky's technique with a screen was used in combination with hemisphere inactivation by means of spreading depression. It was shown during a short-term adaptation to the experimental conditions, in extrapolation of movement direction at its multiple presentation, that the left hemisphere dominated in infant rats and the right one in adult rats. An additional adaptation caused the change of the asymmetry sign in the adult animals, which is discussed in terms of prevalence of the visuospatial or the rational component of the extrapolation task.

Age Factors↗
PubMed1981

[Asymmetry of cat visual cortex potentials].

EPs in response to weak and strong stimuli at 200 points of visual cortex in both hemispheres were recorded in acute experiments on 80 anesthetized cats. Individual and species asymmetry of EP in visual cortex was characterized by its bilateral origin, mosaic localization and time stability. Transection of corpus callosum decreased a slight asymmetry and augmented a strong one. The interaction of endogenous and exogenous asymmetries augments the general asymmetry, particularly with a stimulus in a sagital plane. The data obtained suggest a hemispheric specialization in animals.

Animals↗
PubMedDate not supplied

[Comparative characteristics of the topography of functional interhemispheric asymmetry in the visual cortex following exposure to stimuli of different strength].

It has been shown that most animals exhibit functional interhemispheric asymmetry in the visual cortex, which increases with a rise in the intensity of photic stimulation. Interhemispheric asymmetry is characterized by its bilateral origin and mozaic localization. In the intact brain the transcallosal mechanisms provide for weakening a weak asymmetry and intensifying a strong one. This is due to different lateralization of the excitation focus which possesses dominant properties. A conclusion has been drawn that one of the functions of the callosal body consists in modulating the functional interhemispheric asymmetry.

Animals↗
PubMedDate not supplied

[The topography of functional interhemispheric asymmetry in the visual cortex].

Functional interhemispheric asymmetry was investigated by evoked potentials method in experiments on ten cats under ethaminal anaesthesia at 200 points of the visual cortex during the action of binocular and monocular photic flashes of submaximal intensity. Topographic maps have been plotted of the functional interhemispheric asymmetry. In most of the animals a hemisphere dominant and non-dominant at the given moment can be singled out. Section of the callosal body leads to reduction of the functional interhemispheric asymmetry due to a decrease of the focus of maximum activity in the dominant hemisphere and its increase in the non-dominant one. A mozaic pattern of functional interhemispheric asymmetry has been demonstrated, as expressed in the existence of zones of inverse dominance along with prevailing zones of direct dominance. Section of the callosal body produced a decrease in the area of direct dominance and an increase in that of inverse dominance. Absolute interhemispheric asymmetry was most pronounced in the central part of the visual cortex (field 18 and its medial boundary) and the relative one, on the periphery of the visual area (fields 17 and 19).

Animals↗
PubMedDate not supplied

[The characteristics of motor asymmetry in the ontogeny of calves].

The side of preference (first turn of head) was recorded in calves in situation of free equal probability two-sides choice, and rate of reconstruction of conditioned reflex to food presented from the left or from the right was determined. Initially the calves preferred the left turn, i.e. manifested motor asymmetry. Preference to the left turn changed depending on the calves age with the period of 22-23 days. The rate of conditioned reflexes reconstruction was higher in calves with the left-side preference. Correlation of the motor asymmetry and rate of conditioned reflex reconstruction in calves of different age changed in analogy with age changes of asymmetry. Probably the observed periodical changes of asymmetry and its correlation with the rate of reconstruction reflect formation of interhemispheric interactions in regulation of the organism functions in animals ontogenesis.

Animals↗
PubMedDate not supplied

[The effect of gonadectomy on interhemispheric asymmetry in rats].

The influence was studied of the gonadectomy in the newborn and mature male and female rats on functional interhemispheric asymmetry of the reaction of avoidance of pain scream of another rat ("emotional resonance"), and motor and investigatory activity in the open field. Consecutive inactivation of the hemispheres was realized by K+ spreading depression. It has been shown that neonatally gonadectomized rats have no interhemispheric asymmetry of the studied reactions. In male rats gonadectomized in mature state, interhemispheric asymmetry of "the emotional resonance" reaction is not significant and in the motor and investigatory activity in the open field, in contrast to intact animals, the right hemisphere is dominant and not the left one. Ovariectomy of mature female rats led to the increase of the dominance of the left hemisphere in the control of "the emotional resonance" and change of the right hemispheric dominance in the control of the motor and investigatory activity in the open field for the left hemispheric one. Gonadectomy of male and female mature rats had an opposite effect on the functioning of the right hemisphere: facilitating in male rats and inhibitory in female ones.

Animals↗
PubMedDate not supplied

[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.

Animals↗
PubMedDate not supplied

[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.

Animals↗
PubMedDate not supplied

[Interhemispheric asymmetry of the exploratory and emotional characteristics of rat behavior in the open field].

Interhemispheric asymmetry of motor activity as well as of emotional and investigating behaviour of male and female rats was studied in the open field. With this purpose during 1 hour the number of square intersections, raising to hinds and peeping into the holes as well as the number of defecations and urination was recorded in intact rats and rats with unilateral decortication. Inactivation of the hemispheres was carried out by means of potassium spreading depression. In male rats, in the first minutes of the exposition and in the second part of the session the left hemisphere dominated during motor and investigating activities. In female rats in the second part of the experiments the right hemisphere dominated. For emotional reactivity the left hemisphere dominated in male rats.

Animals↗