Discussion of Eban-Rothschild et al., Nature Neurosci 19, 1356, 2016

Dopamine release from the VTA causes arousal, whereas suppression promotes sleep, as optogenetically clearly demonstrated . Very nice behavioral assessments defining nesting scores and looking at arousal responses to fox odor! We were a bit concerned by the way animals pick up lost sleep after VTA-induced arousal: patterns of sleep rebound are dramatically altered in favor of recovering lost REM but not non-REM sleep. Strikingly reminiscent of psychostimulant effects on sleep-wake behavior??