Effects of prefrontal cortex lesions on spontaneous sleep-wake patterns and compensatory response to sleep loss in rats

Abstract

Recent evidence suggests a possible role for the prefrontal cortex (PFC) in sleep/wake regulation and sleep-related electroencephalogram (EEG) activity. This study investigated the effects of cell-specific ibotenic acid lesions to the PFC on sleep-wake patterns and the EEG under baseline conditions and during recovery from a 6 h period of sleep deprivation (SD) using gentle handling in rats. Control rats were injected with saline. PFC lesions had no effects on overall amounts of wake, non rapid-eye movement (NREM) sleep, or rapid-eye movement sleep. However, lesioned animals had fewer wake and NREM sleep episodes and longer mean durations of these episodes particularly during the dark phase. Following SD, no significant lesion effects were observed in sleep rebound or homeostatic increase in NREM EEG delta power (a measure of sleep intensity). These results suggest a role for the PFC in sleep-wake regulation, in particular behavioural state stability.