THERMOSENSITIVE NEURONS OF THE DIAGONAL BAND IN RATS - RELATION TO WAKEFULNESS AND NON-RAPID EYE-MOVEMENT SLEEP

The thermosensitivity of the neurons in the diagonal band of Broca (DB B) was studied in 12 freely moving rats by determining responses to lo cal cooling or warming with a water perfused thermode. Of 151 neurons studied, 37 (25%) neurons met the criterion for thermosensitivity incl uding 17 warm-sensitive (WSNs) and 20 cold-sensitive neurons (CSNs). T he spontaneous discharge rates of WSNs and CSNs were recorded through 1-3 sleep-waking cycles. The discharge of WSNs and CSNs during waking and non-rapid eye movement (NREM) sleep were different. Of 17 WSNs, 10 exhibited increased discharge rates during NREM sleep as compared wit h waking (NREM/Wake discharge ratio, greater than or equal to 1.2). Of 20 CSNs, 14 discharged more slowly during NREM sleep as compared with waking (NREM/Wake discharge ratio, less than or equal to 0.8). In bot h WSNs and CSNs, changes in discharge rate preceded EEG changes at the waking-NREM transition. These results support a hypothesis that the a ctivation of sleep-related WSNs and the deactivation of wake-related C SNs play a role in the onset and regulation of NREM sleep.