Sleepwalking, or somnambulism, involves walking and other behaviors that are performed during incomplete arousal from sleep. In this video, I discuss some hypotheses about what happens in the brain to cause sleepwalking. TRANSCRIPT: Sleepwalking, or somnambulism, involves walking and other behaviors that are performed during incomplete arousal from sleep. Sleepwalking episodes can last for anywhere from a few seconds to longer than 30 minutes, and sleepwalking behaviors can vary in their complexity from basic behaviors such as pointing or walking around a room, to complicated procedures like getting dressed, cooking, or driving a car. Sleepwalkers may be difficult to arouse during a sleepwalking episode and confused when they awake from one, and they may have complete or partial amnesia for the episode. Sleepwalking occurs more frequently in children than in adults, but childhood sleepwalking is typically benign, while adult sleepwalking is more likely to result in injury to the sleepwalker or others. During sleep, the brain transitions through several stages characterized by unique patterns of brain activity. Sleepwalking typically occurs during stage 3 non-rem sleep, also known as slow-wave sleep. The neuroscience underlying sleepwalking is not completely understood, but current evidence suggests that it may emerge from a coexistence of wake and sleep-like activity occurring in different parts of the brain at the same time. For example, some studies of sleepwalkers during sleepwalking episodes have found brain activity suggestive of wakefulness in areas like the motor cortex, which is involved with movement, but activity suggestive of slow wave sleep in areas involved in complex cognition and conscious awareness, such as the prefrontal cortex. This type of incongruity might explain why sleepwalkers move around with limited awareness of their actions. Wake-like activity during sleep in other areas of the brain—such as those involved in emotional reactions—could explain other aspects of sleepwalking, such as the fact that many sleepwalkers report experiencing strong emotions associated with their episodes. On the other hand, persistence of sleep states in areas like the hippocampus, which is involved in memory consolidation, could explain why sleepwalkers sometimes do not remember the sleepwalking incident or certain aspects of it. REFERENCES: Arnulf I. Sleepwalking. Curr Biol. 2018 Nov 19;28(22):R1288-R1289. doi: 10.1016/j.cub.2018.09.062. Epub 2018 Nov 19. PMID: 30458142. Zadra A, Desautels A, Petit D, Montplaisir J. Somnambulism: clinical aspects and pathophysiological hypotheses. Lancet Neurol. 2013 Mar;12(3):285-94. doi: 10.1016/S1474-4422(12)70322-8. PMID: 23415568. Credit to cottonbro studios for photo of sleepwalker.