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 effects of psychoactive drugs.

Sleep Paralysis

Characteristics and Cultural Influences

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

• Symptoms: Feeling of being conscious but unable to move, anxiety/terror, sensation 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 Rhythm

Biological Rhythms and Regulation

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

• Regulation: Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus, which acts as the brain's clock mechanism.

• Synchronization: The SCN receives light information from the retina, allowing it to synchronize the body's rhythms 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 characterized by low physical activity and a reduced sense of awareness. It is associated with the secretion of several hormones that regulate bodily functions.

• Key hormones:

  • Melatonin

  • Follicle stimulating hormone (FSH)

  • Luteinizing hormone (LH)

  • Growth hormone

Stages of Sleep

Sleep Architecture and Brain Activity

Sleep occurs in cycles of approximately 90 minutes, consisting of five distinct stages. These stages are divided into NREM (Non-Rapid Eye Movement) and REM (Rapid Eye Movement) sleep.

• Stages 1 to 4: NREM Sleep

  • No eye movements, fewer dreams.

  • Progressive slowing of brain waves.

• Stage 5: REM Sleep

  • Vivid dreams and rapid eye movements.

  • Brain activity similar to wakefulness.

Stage 1: Transition

This stage marks the transition from wakefulness to sleep, lasting about 0–15 minutes. Brain waves begin to slow down, and dreams may resemble photographic images.

Stage 2: Falling Asleep

Further slowing of brain waves occurs, with the appearance of sleep spindles and K-complexes. This stage may play a role in maintaining sleep and memory storage. It constitutes up to 65% of total sleep and lasts around 20 minutes.

Stages 3 and 4: Deep Sleep

These stages are characterized by delta waves and are crucial for feeling rested. Growth hormone production is highest, and children spend more time in these stages than the elderly. Deep sleep is suppressed by alcohol, and stage 4 is the hardest to awaken from.

Stage 5: REM Sleep

REM sleep features rapid eye movements, vivid dreams, and brain waves similar to wakefulness. The body is paralyzed (except for inner ear movements), and this stage is considered essential for cognitive and emotional health.

Hypnagogic State: Pre-Sleep Consciousness

Imagery and Sensations

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

• Types of hypnagogic imagery:

  • Visual

  • Somatic (bodily sensations)

  • Auditory

• Hypnic jerk: Sudden muscle contractions that may occur during this state.

Table: Stages of Sleep and Key Features

Stage	Type	Brain Waves	Key Features
Stage 1	NREM	Alpha to Theta	Transition, light sleep, hypnagogic imagery
Stage 2	NREM	Sleep spindles, K-complexes	Memory consolidation, 65% of sleep
Stage 3	NREM	Delta	Deep sleep, growth hormone release
Stage 4	NREM	Delta	Deepest sleep, hardest to awaken
Stage 5	REM	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