3. Why We Avoid: The Psychology of Escape, Avoidance and Fear

Why would someone punch, kick or leap out of bed in the middle of a dream, and why might it be a warning sign of Parkinson's disease years later? In this episode, we close our five-part series on sleep disorders with REM sleep behaviour disorder (RBD), the most important early warning sign in sleep medicine. We tell the story of Carlos Schenck and Mark Mahowald, who first described the condition. We explore the brainstem circuit in the pons that normally paralyses us during REM sleep, and why...

Why can someone walk, talk, or even drive while their brain is still partly asleep? In this episode, we explore the disorders of arousal from non-REM sleep: confusional arousals, sleepwalking, sleep terrors (also known as night terrors), and sleep-related eating disorder. We look at the neuroscience of "local sleep," where the motor cortex wakes while the frontal cortex and hippocampus stay in slow-wave sleep, explaining the amnesia and confusion. We cover genetics and family risk, triggers i...

What if you slept twenty hours a day for weeks at a time, then woke up with barely any memory of it? In this episode, we explore Kleine-Levin syndrome, the rare recurrent hypersomnia nicknamed Sleeping Beauty syndrome, affecting roughly one to five people per million. We cover what an active episode looks like, and the classic three Hs of hypersomnia, hyperphagia and hypersexuality. We look at what brain imaging reveals about the circuits involved, with reduced blood flow in the thalamus and ...

What happens in the brain when a burst of laughter makes your knees give way, while you stay completely awake? In this episode, we explore narcolepsy through the lens of the brain's sleep-wake circuitry. We cover the classic tetrad of excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations, and the difference between narcolepsy type 1 and type 2. We tell the story of Emmanuel Mignot's decade-long hunt through a colony of narcoleptic dogs, and how it led to the d...

If you were told, right now, that you could lie down and fall asleep within five minutes, would your body actually believe you? For most people with insomnia, the honest answer is no, and that gap sits at the centre of the entire disorder. In this episode, we open a five part series on sleep disorders, classified according to ICD-11. We cover how insomnia disorder is actually defined and diagnosed, the two-process model of normal sleep, the hyperarousal model and Spielman's 3P model of how in...