Why Does Your Body Jerk Right Before You Fall Asleep?

You are almost asleep. The room has faded. Then your whole body jolts, your leg kicks, and your heart is pounding for no reason at all. It is called a hypnic jerk, and around two thirds of people get them. But the strangest part is not the jerk itself. It is what your brain does immediately afterwards - and the order those two things actually happen in. Sources and further reading: Sleep-onset physiology and motor atonia: Sleep Medicine Reviews Hypnic jerk prevalence: polysomnography studies, 60-70% of adults Postdiction and backdated conscious timing: Eagleman & Sejnowski, Science 2000 Sleep paralysis prevalence: Sharpless & Barber, Sleep Medicine Reviews 2011 Sleep paralysis intruder phenomenology: Cheyne et al., 1999 Split-brain confabulation: Gazzaniga's interpreter experiments Chapters and sources are drawn from published research. Where a claim is a hypothesis rather than a finding - such as the falling-from-trees explanation it is flagged as one in the video. #hypnicjerk #sleep #neuroscience