Barchi Library, 140 John Morgan Building
Department of Neuroscience
University of Pennsylvania
Brainstem Circuits Controlling REM Sleep
Rapid eye movement (REM) sleep is a distinct brain state associated with vivid dreams. Although the brainstem has been long known to be crucial for REM sleep generation, the underlying circuit remains poorly understood. Combining optogenetics with electrophysiological in vivo recordings, I discovered a group of inhibitory neurons in the ventral medulla (vM) that powerfully promote REM sleep. Using viral tracing techniques, I further showed that vM GABAergic neurons innervate the ventrolateral periaqueductal grey (vlPAG), a midbrain region that strongly suppresses REM sleep by blocking transitions from NREM to REM sleep. Cell-type-specific in vivo recordings and calcium imaging using microendoscopes showed that most vlPAG GABAergic neurons are strongly suppressed at REM sleep onset and activated at its termination. Inhibition of REM sleep-suppressing neurons in the vlPAG by REM sleep-inducing neurons in the vM might thus trigger transitions from NREM to REM sleep. These results cast the interaction between vM and vlPAG as a crucial circuit controlling REM sleep.
A pizza lunch will be served.