Spontaneous discharge of single neurons during sleep and waking.

Populations of single neurons in visual cortex, middle suprasylvian association cortex, and brain stem of cat show greater variance of spontaneous discharge rates during waking than during sleep; this change in variance occurs in the absence of significant changes in mean discharge rates. Neurons which discharge rapidly during sleep tend to discharge even more rapidly during waking, whereas neurons with relatively low rates of discharge during sleep tend to have reduced spontaneous activity during waking.