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: Normal awareness of self and environment.

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

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, anxiety/terror, feeling of a menacing presence.

• Hallucinations: Intruder, vestibular-motor, and chest pressure sensations.

• Cultural influences: Cultural beliefs shape the content and interpretation of sleep paralysis (e.g., 'Old Hag' in Newfoundland, 'Kanashibari' in Japan, 'Top-hat man' in recent Western culture, 'Pandafeche' in Italy).

Circadian Rhythm

Biological Clock and Regulation

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

• Regulation: Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus.

• Light synchronization: SCN receives light information from the retina to synchronize the body's clock with the external environment.

• Physiological effects: Body temperature, hormone production, and blood pressure follow circadian rhythms.

What is Sleep?

Physiological and Hormonal Aspects

Sleep is a state of low physical activity and reduced awareness, essential for health and well-being.

• Hormones secreted during sleep:

  • Melatonin

  • Follicle stimulating hormone

  • Luteinizing hormone

  • Growth hormone

Stages of Sleep

Sleep Cycle and Brain Activity

Sleep occurs in cycles of approximately 90 minutes, consisting of five stages. Stages 1-4 are non-REM (NREM) sleep, and stage 5 is REM sleep.

• NREM (Stages 1-4): No eye movements, fewer dreams.

• REM (Stage 5): Vivid dreams, rapid eye movements.

Stage 1: Transition

• Transition from wakefulness to sleep (0-15 minutes).

• Brain waves slow down.

• Dreams resemble photographic images.

Stage 2: Falling Asleep

• Further slowing of brain waves.

• Appearance of sleep spindles and K-complexes (may help maintain sleep and memory storage).

• Comprises up to 65% of total sleep; lasts around 20 minutes.

Stage 3 and 4: Deep Sleep

• Characterized by delta waves.

• Crucial for feeling rested and for growth hormone production.

• Children spend more time in deep sleep than elderly.

• Suppressed by alcohol.

• Stage 4 is the hardest to awaken from.

Stage 5: REM Sleep

• Rapid eye movement sleep.

• Brain waves similar to wakefulness (paradoxical sleep).

• Body is paralyzed, but brain is highly active.

• Essential for cognitive function and emotional regulation.

Hypnagogic State: Pre-Sleep Consciousness

• Occurs during the transition into sleep.

• Features hypnagogic imagery: visual, somatic, and auditory sensations.

• May include myoclonic/hypnic jerks.

Table: Stages of Sleep and Key Features

Stage	Type	Brain Waves	Key Features
1	NREM	Alpha to Theta	Transition, slow waves, photo-like dreams
2	NREM	Theta, Sleep spindles, K-complexes	Memory consolidation, 65% of sleep
3	NREM	Delta	Deep sleep, growth hormone
4	NREM	Delta	Deepest sleep, hardest to awaken
5	REM	Beta (similar to wakefulness)	Vivid dreams, rapid eye movement, body paralysis

Additional info:

• Sleep is essential for memory consolidation, learning, and cognitive function.

• Disruptions in sleep (e.g., sleep deprivation, shift work) can have significant effects on mental and physical health.