Consciousness: Sleep, Dreams, and Drugs – Psychology Study Notes

Consciousness

Definition and Perspectives

Consciousness refers to our subjective experience of the world, our bodies, and our mental perspectives. It encompasses both waking consciousness and various altered states.

• Waking consciousness: Awareness of self and environment during normal wakefulness.

• Altered states of consciousness: Includes sleep paralysis, locked-in syndrome, out-of-body experiences, near-death experiences, mystical experiences, hypnosis, meditation, and psychoactive drug effects.

Sleep Paralysis

Characteristics and Cultural Influences

Sleep paralysis is a phenomenon where an individual is conscious but unable to move, typically occurring when waking up or falling asleep, especially during transitions in and out of REM sleep.

• Symptoms: Inability to move, feelings of anxiety or terror, and a sense of a menacing presence.

• Hallucinations: Intruder, vestibular-motor, and chest pressure hallucinations are common.

• Cultural influences: The content and interpretation of sleep paralysis experiences are shaped by cultural beliefs (e.g., 'Old Hag' in Newfoundland, 'Kanashibari' in Japan, 'Top-hat man' in recent Western reports, 'Pandafeche' in Italy).

Circadian Rhythms

Biological Clock and Regulation

Circadian rhythms are biological cycles that repeat approximately every 24 hours, regulating sleep, hunger, concentration, and other physiological processes.

• Suprachiasmatic nucleus (SCN): The brain's clock mechanism, located in the hypothalamus, synchronizes with external light via retinal projections.

• Sleep-wake cycle: Linked to environmental light-dark cycles, influencing body temperature, hormone production, and blood pressure.

What is Sleep?

Physiological Aspects

Sleep is characterized by low physical activity and a reduced sense of awareness. It is associated with the secretion of several hormones:

• Melatonin: Regulates sleep-wake cycles.

• Follicle stimulating hormone (FSH): Involved in reproductive processes.

• Luteinizing hormone (LH): Also involved in reproduction.

• Growth hormone: Promotes growth and cellular repair.

Stages of Sleep

Sleep Architecture

Sleep occurs in cycles of approximately 90 minutes, consisting of five stages:

• Stages 1-4: NREM (Non-Rapid Eye Movement) Sleep

  • No eye movements, fewer dreams.

  • Stage 1: Transition from wakefulness to sleep (0-15 minutes), slowing brain waves, brief photo-like dreams.

  • Stage 2: Further slowing of brain waves, presence of sleep spindles and K-complexes (may aid in memory storage and maintaining sleep).

  • Stage 3 & 4: Deep sleep, characterized by delta waves, crucial for feeling rested and growth hormone production. Children spend more time in these stages than the elderly. Stage 4 is the hardest to awaken from and is suppressed by alcohol.

• Stage 5: REM (Rapid Eye Movement) Sleep

  • Vivid dreams and quick eye movements.

  • Brain waves resemble wakefulness; body is paralyzed (paradoxical sleep).

Hypnagogic State

The hypnagogic state is the transitional period before sleep, marked by vivid imagery and sensations.

• Hypnagogic imagery: Can be visual, somatic (bodily), or auditory.

• Myoclonic/hypnic jerk: Sudden muscle contractions often experienced during this state.

Summary Table: Stages of Sleep

Stage	Type	Key Features	Brain Waves
Stage 1	NREM	Transition, light sleep, photo-like dreams	Slowing alpha/theta
Stage 2	NREM	Sleep spindles, K-complexes, memory consolidation	Theta + spindles/K-complexes
Stage 3	NREM	Deep sleep, restorative, growth hormone	Delta
Stage 4	NREM	Deepest sleep, hardest to awaken	Delta
Stage 5	REM	Vivid dreams, rapid eye movement, body paralysis	Similar to wakefulness

Example

A person cycles through these stages multiple times each night, with REM periods becoming longer in later cycles.

Additional info: These notes expand on the brief points in the slides, providing definitions, physiological context, and a summary table for clarity.