Effects of sleep deprivation on awakening thresholds and sensory evoked potentials in the rat.

The EEG desynchronization response to stimuli presented during slow-wave sleep was studied in 25 chronically implanted rats after 12 hr of sleep deprivation and during control periods of normal sleep. Compared to normal sleep, sleep after deprivation was accompanied by a significant decrease in the number of EEG desynchronization responses to auditory stimuli and by an additional disproportionate decrease in the number of sustained desynchronization responses. Thalamic auditory evoked potentials were not reduced in amplitude during postdeprivation sleep, thus the decrease in number of EEG desynchronization responses to the auditory stimuli was apparently not mediated by decreased responsiveness in the peripheral auditory system. On the other hand, postdeprivation sleep was not accompanied by any significant change in total number of EEG desynchronization responses to direct trigeminal nerve stimulation nor by any change in the duration of responses to trigeminal stimulation. The results suggest that recovery from sleep loss in accompanied not by a nonspecific increase in the threshold for arousal per se but instead by a selective increase in the threshold for arousal to certain classes of peripheral stimuli.