[The neuronal organization of the amygdala-visceral reflex arch]

The paper summarizes the histomorphic, histochemical, autoradiographic, immune-histochemical and electrophysiological data on the structural-functional organization of the amygdalar complexes. While discussing the problem of neuron organization of the afferent and efferent groups in the amygdala-visceral arch the authors present their data of microelectrophysiological studies of the specific amygdala neuron reactions in response to stimulation of the vagus, ventric, and sciatic nerves, and of the second somatic sensor cortex zone. It was observed that interoceptive impulsation reaching the polysensor neurons of the central, corticomedial, and basolateral groups of the amygdala complex nuclei have no significant qualitative differences. A series of experiments demonstrated that the polysensor convergent amygdala neurons are also polyeffectoral. Comparative studies of the sympathetic discharges in the white connecting branches produced by stimulation of the above nuclear amygdala groups, confirmed absence of a clear topographic localization of the sympatho-activating structures within an amygdala. Comparative exploration of the parasympathetic discharges in the pelvis nerve discovered a discharge of complex configuration in response to simulation of the pelvis nerve nuclei. There was no notable topographic localization of the amygdala parasympathoactivating structures. The system's arterial pressure was studied in response to stimulation of various amygdala structures. Low-frequency stimulation (5 Hertz) of all amygdala structures produces depressor reactions, high-frequency stimulation (100 Hertz) produces pressor reactions. Microelectrophysiological data are provided on the specific reactions of the inspiration and expiration neurons of the bulbar respiratory centre under frequency stimulation of various amygdala structures. The authors have concluded that the bulbar-spinal mechanisms regulating the vegetative functions are implemented by polysensoral-polyeffectoral integrative amygdala neurons of the convergent-divergent type. Consequently, there are no separate populations of the sympatho-activating and parasympathoactivation neurons and of the selective structures regulating the respiratory and the cardiovascular functions.