Oculomotor outflow and its relation to electrical activity of suprasylvian gyrus and pulvinar during paradoxical sleep in the cat

Abstract

During paradoxical sleep, single unit activity was recorded from the posterior part of the middle suprasylvian cortex together with the electrical activity of the medial rectus eye muscles and that of the pulvinar nucleus. Experiments were performed on unrestrained cats, which slept in a dark cage. The intervals between the onsets of the successive phasic ocular EMG bursts were determined. There was a pronounced occurence of intervals lasting 120–240 msec. The mean discharge rate of the suprasylvian cells during the 200 msec period after the onset of EMG bursts of brief duration was significantly higher than during the 200 msec period before the onset of such EMG bursts. The greatest increase in the mean discharge rate took place during the first 40 msec after the onset of the EMG bursts. A distinct theta activity was seen in the pulvinar during most of the recording time. Its frequency and amplitude varied in general relation to the occurence and rate of the phasic ocular EMG bursts.