Spike activity of neurons in the amygdala and hypothalamus in bilateral leads in food motivation.

Measurements of mean spike frequencies and plotting of autocorrelation histograms were performed to study the nature of the spike activity of individual neurons in the lateral hypothalamus and central nucleus of the amygdala from bilateral leads in rabbits in calm waking, after 24-h food deprivation, and after satiation. The nature of neuron spike activity changed in different ways in the hypothalamus and amygdala on transfer from hunger to satiation: 1) the mean spike frequency changed in more hypothalamic (85%) than amygdalar (56%) cells; 2) as compared with calm waking and satiation, hunger was associated with a decrease in the number of neurons with periodic discharges in the delta frequency range in the hypothalamus, while the amygdala showed an increase in periodic discharges in the beta-2 frequency range; 3) in hunger, the hypothalamus showed a decrease in the number of neurons with burst and periodic discharges, while the amygdala showed increases in the number with equiprobabilistic discharge activity. Assessed in terms of autocorrelation histogram shape, greater changes in the nature of neuron spike activity associated with changes in state occurred on the left side than on the right in both the hypothalamus and amygdala. The maximal differences in neuron spike activity on the right and left sides in the hypothalamus were seen in hunger; the greatest differences in the amygdala were seen in satiation.