We studied the effects of total sleep deprivation and recovery sleep in normal subjects using position emission tomography with 18F-deoxyglycose. Sleep deprivation resulted in a significant decrease in relative metabolism of the frontal cortex, thalamus, and striatum. Recovery sleep was found to have only a partial restorative effect on frontal lobe function with minimal reversal of subcortical deficits. Sleep may be especially important for maintenance of frontal lobe activity.