Sleep Deprivation, Sleep Disorders, and Dreams

Effects of Sleep Loss

  • Sleep Debt Accumulation

    • Accumulated after 5 hour sleeps, cannot be restored by one long night of sleep.

  • Mental Health

    • Sleep loss is a predictor for depression.

    • REM sleep's role in processing emotional experiences protects against depression.

  • Cognitive Impact

    • Sleep deprivation causes:

    • Difficulty studying

    • Diminished productivity

    • Increased tendency to make mistakes

    • Irritability and fatigue

  • Physical Health

    • Suppresses immune cells fighting viral infections and cancer.

    • Those sleeping 7-8 hours chronically tend to outlive sleep-deprived individuals.

  • Weight Management

    • Increased ghrelin (hunger-arousing hormone)

    • Decreased leptin (hunger-suppressing hormone)

    • Increased cortisol (stress hormone), stimulates fat production.

  • Performance Tasks

    • Slows reactions and attention tasks, increases visual errors (e.g., driving, piloting).

    • Notable industrial accidents have occurred due to operator drowsiness after midnight.

Sleep Disorders

  • Narcolepsy

    • Characterized by uncontrollable sleep attacks.

    • Affects direct transition into REM sleep at inappropriate times.

    • Results from absence of hypothalamic neural center producing orexin (hypocretin), a neurotransmitter linked to alertness.

  • Sleep Apnea

    • Characterized by temporary cessations of breathing during sleep and repeated awakenings.

    • Intermittent breathing stops can happen 100+ times a night, depriving individuals of slow-wave sleep.

    • Commonly associated with loud snoring, obesity, daytime sleepiness, irritability, and high blood pressure.

  • Night Terrors

    • Involves arousal during sleep with an appearance of terror, occurring in NREM-3 sleep phase.

    • Most common in children; episodes include rapid heart/breathing rates, little memory afterwards.

  • Sleepwalking/Sleeptalking

    • Common childhood disorders, linked with lengthy NREM-3 sleep cycles.

    • Tendency diminishes with age; increased sleep deprivation can lead to more sleepwalking episodes.

Dreams

  • Definition

    • Sequences of images, emotions, and thoughts that pass through the sleeping mind, characterized by hallucinatory imagery, discontinuities, and delusional acceptance.

    • We spend approximately 6 years of our lives dreaming.

    • Common themes: being attacked, failing, being pursued/rejected.

  • Connection to Daily Life

    • Dreams reflect traces of daily experiences; trauma can lead to nightmares, while hunter-gatherer societies dream more about animals.

  • Memory Monitoring During Sleep

    • External stimuli (e.g., noise, odor) can influence dreams.

Why We Dream

  • Freud's Theories

    • Manifest Content: The remembered storyline of a dream.

    • Latent Content: The hidden meaning behind the dream.

    • Unconscious drives/wishes that may be threatening if exposed directly.

    • Critics argue Freud’s theories lack scientific basis.

  • Information Processing Perspective

    • Sleep helps in filing away memories.

    • Those who are sleep-deprived show poorer performance in tests, linking REM sleep to memory.

  • Cognitive Development

    • Dreams may stimulate cognitive development by processing knowledge and experiences.

    • Also provide periodic stimulation necessary for strengthening neural pathways.

REM Sleep

  • Importance of REM Sleep

    • Necessary for cognitive functioning, emotional regulation, and memory consolidation.

    • REM rebound effect - tendency for REM sleep to increase following deprivation, indicating its importance for health.