CSB neurobiologists identify switch that turns muscles on and off during sleep

CSB Professor John Peever, CSB PhD grad Zoltan Torontali and CSB RA Jimmy Fraigne have demonstrated a new link between arousal and muscle paralysis in mice using behavioral, electrophysiological, and chemogenetic strategies in a paper in Current Biology.
During REM sleep, muscle paralysis is induced by a region of the brain called the Sublaterodorsal Tegmental Nucleus (SLD). Involuntary muscle paralysis during wakefulness can occur in the natural phenomenon of cataplexy, whereas sleep is involuntarily induced in narcolepsy.
Prof Peever’s lab found that activation of SLD neurons in both narcoleptic and normal mice promotes cataplexy, whereas SLD silencing prevents cataplexy. This region of the brain therefore couples arousal state and motor activity during REM sleep and wakefulness.
This new understanding has the potential to treat muscular disorders in humans. In Parkinsons’s disease, the affected person’s muscles are in a continual state of rigour during wakefulness, but this rigour relaxes during REM sleep. Prof Peever dreams of helping Parkinson’s patients by applying this new understanding of the SLD to tune their muscle tension during wakefulness.
You can read more about this insight in a story from UofT News and in the Current Biology paper.