Comparative analysis of spike activity of neurons in hippocampal field CA1 and CA3 in rats of different typological groups on exposure to emotional stimuli.

Spike activity from neurons in hippocampal field CA1 and CA3 was compared in rats avoiding ("altruists," group A) and not avoiding ("egoists," group E) the cries of a "victim" partner on testing using the emotional resonance method. Neuron discharge frequencies were compared in animals in the state of starvation, after satiation, and on exposure to emotionally positive and negative intracerebral electrical stimuli. These studies showed that hippocampal field CA1 was dominated by cells increasing their spike frequencies after satisfaction of the food motivation, while in field CA3, conversely, most cells decreased activity after eating. Exposure to emotionally significant stimuli identified interhemisphere differences in the activities of hippocampal neurons which were associated with the typological characteristics of the animals. In rats of group A, neurons in field CA1 were activated only in the left hippocampus, while the activity of cells in the right hippocampus was no different from that in baseline conditions. Field CA3 of rats of this group showed no asymmetry. In rats of group E, conversely, lateralization of activity was seen only in field CA3: discharge frequencies were significantly greater in the left hippocampus.