Sleep Disorders and Neuropsychology Quiz

Sleep Disorders and Neuropsychology

• Sleep is a complex process with different stages regulated by neural and physiological mechanisms
• Understanding sleep requires exploring brain structures, neurochemicals, and processes involved in transitioning between stages

Sleep Stages

• Sleep cycle consists of Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) sleep
• NREM and REM alternate throughout the night in cycles
  • NREM Sleep
    • Stage 1 (N1): Transition stage between wakefulness and sleep, light sleep with theta waves (3-8 Hz)
    • Stage 2 (N2): Deeper stage of light sleep with sleep spindles and K-complexes
    • Stage 3 (N3): Deep sleep, or slow-wave sleep (SWS), characterized by delta waves (0.5-4 Hz) essential for restorative functions (tissue growth, repair, memory consolidation)
  • REM Sleep
    • REM sleep occurs primarily after NREM sleep, associated with vivid dreams, rapid eye movement, low muscle tone, and brain activity resembling wakefulness (beta waves 12-30 Hz)
  • REM sleep is crucial for learning, memory, and emotional regulation, occurring about 20-25% of sleep time for adults and typically appears 90 minutes after falling asleep, repeating multiple times per night
    • Sleep cycle typically lasts around 90 minutes, with NREM and REM alternating regularly, and a typical night's sleep will have between four and six such cycles, with more deep sleep earlier and more REM sleep later.

Neuroscience of Sleep

• Brain Regions
  • Suprachiasmatic Nucleus (SCN): Located in the hypothalamus, acts as the body's biological clock regulating sleep-wake cycle based on light-dark cues, controls melatonin release from the pineal gland.
  • Hypothalamus: Regulates sleep through sleep-promoting substances and sleep-inducing brain areas
  • Reticular Activating System (RAS): A network in the brainstem that regulates wakefulness and arousal; helps facilitate sleep.
  • Thalamus: Blocks sensory information from reaching the cortex during NREM sleep, so the brain can focus on internal processes instead.
  • Amygdala: Involved in processing emotions, active during REM sleep, and plays a role in emotional regulation through dreaming
• Neurotransmitters
  • GABA (Gamma-Aminobutyric Acid): Inhibitory neurotransmitter that initiates and maintains NREM sleep
  • Adenosine: Byproduct of energy consumption, promotes sleep by inhibiting wake-promoting neurons.
  • Melatonin: Hormone produced by the pineal gland that signals sleep onset and regulates the circadian rhythm
  • Orexin (Hypocretin): Promotes wakefulness, prevents transitions to REM sleep, dysfunction can lead to narcolepsy
• Neurochemicals
  • Acetylcholine: High levels during REM sleep affecting dream-related brain activity and memory processing.
  • Serotonin and Norepinephrine: Active during wakefulness, but suppressed during REM sleep affecting mood and alertness.

Sleep Disorders

• Disruptions to normal sleep patterns or the sleep cycle lead to various sleep disorders
  • Parasomnias: Abnormal behaviors during sleep (sleepwalking, night terrors, sleep paralysis) disrupting cognitive performance, and emotional stability.
  • Circadian Rhythm Disorders: Problems with the timing of sleep (Jet lag, shift work disorder, delayed sleep phase syndrome) leading to cognitive impairment and mood disturbances.
  • Insomnia: Difficulty falling asleep, staying asleep, or waking up too early. Chronic insomnia can affect attention, memory, and executive functioning.
  • Sleep Apnea: Characterized by repeated interruption of breathing during sleep due to airway obstruction or central nervous system issues leading to fragmented sleep, daytime sleepiness, and cognitive deficits.

Test your knowledge on sleep disorders and the neuropsychological aspects of sleep. This quiz covers the various stages of sleep, including NREM and REM, and their physiological and neural underpinnings. Explore the transitions between sleep stages and their importance for brain function and overall health.