Lecture Notes on Sleep and Sleep Disorders

Sleep Theories

• Importance of sleep in humans and animals is evident; few species don't sleep.

• Restore and Repair Hypothesis: Sleep facilitates body maintenance, such as restoring glycogen and clearing brain waste, but lacks substantial supporting evidence.

• Preserve and Protect Hypothesis: Evolutionary perspective suggesting sleep maximizes safety during vulnerable times; species with higher predatory risks sleep less.

Sleep and Cognitive Function

• Sleep is linked to learning and memory enhancement, especially in youth.

• Research shows that sleep after learning tasks can improve performance (e.g., finger tapping tasks).

• REM sleep (20-25% of total sleep) is crucial for memory; REM rebound occurs after deprivation.

Dreaming Theories

• Dreams occur during non-conscious sleep; elaborate dreams are recalled from REM sleep.

• Freudian Theory: Dreams symbolize unconscious desires (manifest vs. latent content).

• Activation-Synthesis Hypothesis: Dreams stem from brainstem activity interpreted by the cortex, contributing to a proto-conscious state.

Sleep Disorders

• Insomnia: Common sleep disorder impacting daily function, consists of:

  • Onset insomnia: Trouble falling asleep.

  • Maintenance insomnia: Trouble staying asleep.

  • Early-morning insomnia: Waking too early.

• REM Behavior Disorder: Acting out dreams due to a malfunction in REM paralysis.

• Narcolepsy: Rare disorder characterized by excessive daytime sleepiness and direct transition to REM sleep; related to orexin deficiency.

Sleep Tips

• Establish a consistent sleep schedule.

• Associate your bed with sleep, avoid reading.

• Get up if unable to sleep until tired.

• Keep the room cool (around 18.5°C).

• Avoid caffeine and sedatives before bed.