VISCERAL AFFERENT ACTIVITY EFFECTS ON BRAIN STEM RETICULAR FORMATION.

There appears to be regional differences in the reticular core in the sense of a ventro-dorsal and caudo -rostral organization. These results are discussed in relation with histological data obtained by degeneration experiments and physiological results of intra-reticular stimulation or recordings with macro- and micro-electrodes. Special emphasis is put on the fact that the organization disclosed by these stimulation experiments shows good agreement with the distinction of reticular regions mainly occupied by long-exoned neurons responsible therefore for short-lasting activations and the ones mainly occupied by multi-synaptic short -axoned circuits whose role in the long-lasting delayed activation is stressed. Author