Preoptic/anterior hypothalamic warming increases EEG delta frequency activity within non-rapid eye movement sleep.

The effects of mild POAH warming and cooling on EEG frequency patterns within sustained periods of NREM sleep were examined. EEG spectral power analysis showed that POAH warming increased delta (0.5-4.0 Hz) activity, but had no effect on theta or sigma frequencies. Delta power was also increased during a 1 h recovery period, following warming. POAH cooling had no EEG effects. Since delta power is thought to be an index of sleep depth, our findings suggest that POAH thermoregulatory mechanisms participate in the regulation of the depth of NREM sleep.