Instead, they found the cells abruptly promote non-REM sleep and trigger sleep attacks in a mouse model of narcolepsy. By Risa Kerslake, RN, BSNOne of the most distressing symptoms of narcolepsy is sudden, involuntary sleep attacks that can hit patients even during activity. Why these sleep attacks occur is a question researchers are still trying to uncover. While GABA cells were thought to be important for controlling the timing of REM sleep, newer studies have suggested it’s actually glutamate cells in the same region that are essential for REM sleep, according to Fraigne. But the GABA cells are really doing the job of putting the ‘brake’ on wakefulness, and when they’re abnormally activated, they can cause sleep attacks in narcolepsy,” he adds.