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.