Does normal sleep alter regional cerebral blood flow compared to waking states in young adults?
Regional cerebral blood flow in humans varies significantly according to sleep state, increasing during REM sleep and decreasing during slow wave sleep.
dence that increases in neuronal activity occur during rapid eye movement (REM) sleep. Cerebral metabolic rate is also thought to increase, based on indirect evidence that cerebral blood flow (CBF) is elevated during REM sleep in animals. The present study was designed to evaluate changes in human CBF during normal sleep in 11 young adults. A noninvasive regional CBF method was used involving the clearance of inhaled la3Xe, monitored extracranially. In all regions studied (temporal, precentral, and occipital), CBF in the gray matter tissue compartment varied significantly accord-ing to the sleep or waking state. Depending on the brain region, CBF during REM sleep was elevated 3-12 D/ci above afternoon waking levels. In contrast, CBF during slow wave sleep was re-duced S-14oj. These CBF changes could not be accounted for by variations in arterial COZ or blood pressure and thus may re-flect alterations in brain metabolism or in mechanisms controlling
Townsend et al. (Thu,) studied this question.