THE CAUDO VENTRAL PONTINE TEGMENTUM IS INVOLVED IN THE GENERATION OF HIGH-VELOCITY EYE SACCADES IN BURSTS DURING PARADOXICAL SLEEP IN THE CAT

Cat eye movements were recorded in the head restrained condition, with the technique of the scleral search coil in a magnetic field, and the maximum velocity/amplitude relationships were analyzed for saccades i n the following conditions, (1) during waking (W); (2) during paradoxi cal sleep (PS); and (3) during W following carbachol microinjections i n the medioventral part of the caudal pontine tegmentum. These finding s indicate that (1) the neurophysiological mechanisms underlying carba chol induced events are similar to those acting during PS and that the caudal pontine tegmentum might be the generator of high velocity eye saccades in bursts accompanied by ponto geniculo occipital waves (PGOw ) during PS, and (2) caudal pontine tegmentum neurons show 'state-depe ndent' responsiveness to cholinergic inputs, suggesting that a change in the synaptic inputs and/or the membrane properties of these neurons during PS may be responsible for the induction of saccadic eye moveme nts in bursts and associated PGOw.