All puns aside, sleepwalking is a type of parasomnia. Like other parasomnias, sleepwalking typically occurs as your body is trying to wake up from deep slow-wave sleep (Stages 3 and 4 of NREM sleep). The autonomic nervous system, which controls automatic bodily functions like your breathing, is suddenly jolted. Your brain is forced to wake up from its deep sleep but gets stuck in the middle of that and wakefulness. As a result, your brain is in deep sleep, but your body is acting out behaviors as if you were awake.

You may be wondering what’s going on in your brain when you’re sleepwalking. The cerebellum and motor cortex are highly active while the prefrontal cortex (responsible for logical reasoning) shows extremely low activity levels–lower than the levels seen during REM sleep.

Bassetti, C., Vella, S., Donati, F., Wielepp, P., & Weder, B. (2000). SPECT during sleepwalking. The Lancet, 356(9228), 484-485. doi:10.1016/s0140-6736(00)02561-7