Overview
This lecture covers states of consciousness, focusing on sleep stages, sleep disorders, the biological basis of sleep, the effects of psychoactive drugs, and altered states like hypnosis and meditation.
States of Consciousness
- Consciousness refers to our awareness of internal (thoughts, feelings) and external (environmental) stimuli.
- States of consciousness range from full alertness to deep sleep and include daydreaming, intoxication, hypnosis, and meditation.
Biological Rhythms and Sleep Regulation
- Biological rhythms are recurring cycles in body processes, e.g., the menstrual cycle and circadian rhythms.
- Circadian rhythms are 24-hour cycles, like the sleep-wake cycle, regulated by the suprachiasmatic nucleus (SCN) in the hypothalamus.
- Melatonin, released by the pineal gland, regulates sleep and is influenced by light.
- Chronotype refers to individual variations in circadian rhythms (morning lark vs. night owl).
- Disruptions such as jet lag and rotating shift work can misalign circadian cycles, causing sleep disorders and health issues.
- Light exposure can help realign circadian rhythms.
Sleep Debt and Deprivation
- Sleep debt accumulates when people do not get enough sleep regularly, reducing alertness and cognitive function.
- Chronic sleep deprivation is linked to depression, obesity, high blood pressure, and impaired immune function.
- Adults typically need 7–9 hours of sleep per night, but needs vary with age.
Theories and Functions of Sleep
- Brain areas involved in sleep: hypothalamus (SCN), thalamus, and pons.
- Hormones involved: melatonin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and growth hormone.
- Evolutionary theories suggest sleep conserves energy and reduces predation risk, but evidence is mixed.
- Cognitive theory states that sleep enhances memory, learning, and problem-solving.
Sleep Stages
- Sleep is divided into REM (rapid eye movement) and non-REM (NREM) stages.
- NREM Stage 1: Transition from wakefulness, marked by alpha and theta waves.
- NREM Stage 2: Deeper relaxation, sleep spindles, and K complexes.
- NREM Stage 3: Deep sleep, slow delta waves, hard to awaken.
- REM Sleep: Vivid dreaming, brain waves resemble wakefulness, muscle paralysis occurs.
- REM rebound: Extra REM sleep after deprivation, linked to emotional and memory processing.
Dreams and Dream Theories
- Freud: Dreams reveal unconscious desires (manifest and latent content).
- Jung: Dreams tap the collective unconscious and universal archetypes.
- Cartwright: Dreams reflect relevant life events.
- Hobson's activation-synthesis theory: Dreams are the brain's attempt to make sense of neural activity during REM.
- Lucid dreams: Awareness of dreaming, potential control over dream content.
Sleep Disorders
- Insomnia: Difficulty falling or staying asleep; treated with lifestyle changes, therapy, or medication.
- Parasomnias: Disruptive sleep behaviors, including sleepwalking, restless leg syndrome, and night terrors.
- REM Sleep Behavior Disorder (RBD): Lack of muscle paralysis in REM, leading to physical activity during dreams.
- Sleep apnea: Breathing stops during sleep; treated with CPAP devices or other interventions.
- Sudden Infant Death Syndrome (SIDS): Infant dies during sleep; risk reduced by safe sleep practices.
- Narcolepsy: Unexpected sleep episodes, often with muscle weakness (cataplexy); treated with stimulants.
Psychoactive Drugs and Altered States
- Substance use disorders involve compulsive drug use, tolerance, and withdrawal.
- Depressants (e.g., alcohol, barbiturates): Suppress CNS activity, risk of dependence.
- Stimulants (e.g., cocaine, amphetamines, caffeine, nicotine): Increase CNS activity, risk of addiction and health consequences.
- Opioids (e.g., heroin, morphine, codeine): Reduce pain, high risk of dependence and overdose.
- Hallucinogens (e.g., LSD, PCP): Alter perception and sensory experience, less addictive.
- Marijuana: Legal in some states for medical/recreational use; research ongoing.
Hypnosis and Meditation
- Hypnosis: State of focused attention and suggestibility, used therapeutically for pain, depression, and anxiety management.
- Theories of hypnosis: Dissociation (state of divided consciousness) and social-cognitive (acting a social role).
- Meditation: Focuses attention to increase awareness; benefits include stress reduction, improved sleep, and possible health improvements.
Key Terms & Definitions
- Consciousness — Awareness of internal and external stimuli.
- Circadian rhythm — 24-hour biological cycle (e.g., sleep-wake).
- Suprachiasmatic nucleus (SCN) — Brain’s clock that regulates circadian rhythms.
- Melatonin — Hormone that promotes sleep.
- Chronotype — Individual variation in circadian rhythm timing.
- Sleep debt — Cumulative lack of adequate sleep.
- REM sleep — Sleep phase with vivid dreams and rapid eye movements.
- Sleep spindle — Burst of brain activity in Stage 2 NREM.
- K complex — High-amplitude brain wave in Stage 2 NREM, related to arousal.
- Delta wave — Slow, high-amplitude brain wave in deep sleep.
- Insomnia — Difficulty falling or staying asleep.
- Parasomnia — Unusual behaviors during sleep.
- Narcolepsy — Disorder of sudden sleep bouts and muscle weakness.
- Psychoactive drug — Substance altering perception, mood, or behavior.
- Tolerance — Needing more of a drug for the same effect.
- Withdrawal — Negative symptoms after stopping a drug.
Action Items / Next Steps
- Review recommended sleep hours by age group.
- Learn sleep hygiene tips for healthy sleep.
- Read more on psychoactive drugs and their mechanisms.
- Complete assigned readings on theories of dreaming.