[The effect of the phases of the estrous cycle on functional interhemispheric asymmetry in rats]

The functional interhemispheric asymmetry was studied in rats during different phases of the estrual cycle in the tests of emotional resonance (avoidance of pain cry of a conspecific) and the open field locomotor and exploratory activity. Inactivation of hemispheres was accomplished by potassium spreading depression. During the open field activity the left hemisphere dominated in proestrus, the right hemisphere dominated in estrus, in metestrus the dominance of the right hemisphere decreased, and in diestrus the hemispheric asymmetry was not expressed. The neocortex inhibited the emotional avoidance reaction in proestrus and facilitated it in estrus. The left hemisphere dominated in inhibition and the right hemisphere prevailed in activatory influence.