Responses of anterior hypothalamic-preoptic neurons to direct thermal stimulation during wakefulness and sleep.

The responses of anterior hypothalamic-preoptic units to direct thermal stimulation were studied during wakefulness and sleep in cats. Seventy-nine percent of the selected units showed changes in firing rate in relation to wakefulness and sleep stages. Forty-nine percent of the units characterized by activity related to EEG patterns were found to be responsive to thermal stimulation in wakefulness and synchronized sleep. Unit responses to thermal stimulation were either absent or inconsistent in desynchronized sleep.