Some aspects of a study of habituation in visceral systems

The general regularities of habituation in visceral systems according to the Thompson-Spencer criteria were investigated in acute experiments on chloralose-narcotized cats. Changes in systemic reactions (blood pressure and heart rate) and dynamics of neuronal activity in the medulla oblongata and cerebral cortex to repeated long stimulation of visceral (splanchnic and mesenteric) nerves were used as indicators of habituation. It was established that habituation in visceral systems develops more easily in the projection areas of the cortex than in the nuclei of the medulla oblongata. A comparison of the process of habituation in primary and secondary areas of the cortex and nuclei of the medulla oblongata revealed a number of differences in the time and expressivity of the investigated phenomenon: it occurred more rapidly in nonspecific structures of the brain. Recording of the EP in area SI to repeated stimulation of the pelvic nerves of nonnarcotized cats showed that complete habituation is not attained, and there is only a tendency toward a decrease of the amplitude of responses.