Consciousness Study Notes

CHAPTER 5: CONSCIOUSNESS

Learning Objectives

  • 5.1a: Explain the role of the circadian rhythm and how our bodies react to disruption in our biological clocks.

  • 5.1b: Identify the different stages of sleep, alongside the neural activity and dreaming behaviours occurring in each stage.

  • 5.1c: Identify features and causes of sleep disorders.

  • 5.2a: Describe Freud's theory of dreams.

  • 5.2b: Explain three major modern theories of dreaming.

  • 5.3a: Determine how scientists explain unusual and seemingly "mystical" alterations in consciousness.

  • 5.3b: Distinguish myths from realities concerning hypnosis.

  • 5.4a: Identify possible influences on substance use.

  • 5.4b: Distinguish among different types of drugs and their effects on consciousness.

Topic 5.1: Consciousness

  • Defined as our subjective experience of the world, our bodies, and our mental perspectives.

  • Includes alterations of normal consciousness:

    • Sleep Paralysis: Phenomenon wherein resumption of consciousness occurs while muscle atonia of REM sleep is maintained, causing intense fear and inability to move.

    • Locked-In Syndrome: Rare neurological disorder characterized by full consciousness but total paralysis, except for eye movements due to brainstem damage. Communication via blinking is possible.

    • Out-of-Body Experiences, Near-Death Experiences, and Mystical Experiences: These can overlap with sleep phenomena and are associated with unique perceptual experiences.

Why Do We Need Sleep?

  • Sleep is critical for:

    • Learning, long-term memory formation, and emotional information retention.

    • Immune system function enhancement.

    • Promoting insight and problem-solving capabilities.

    • Neural development and connectivity.

    • Energy conservation.

Biology of Sleep

  • Circadian Rhythm: Refers to biological changes that occur on a 24-hour cycle.

    • Includes hormone release and body temperature regulation.

    • Regulated by the Suprachiasmatic Nucleus (SCN), the biological clock located in the hypothalamus.

  • Circadian Rhythm Functionality:

    • Adjustments like melatonin secretion start at 21:00, with peak temperature at 19:00, and lowest temperature at approximately 04:30.

  • Sleep Pressure: Triggered by increasing melatonin, representing a drive for sleep that builds with wakefulness.

How Much Sleep?

  • Recommended sleep duration varies by age:

    • Newborns: approx. 16 hours.

    • College students: approx. 9 hours.

    • Adults: 7-10 hours.

    • Individuals with DEC2 Mutation (<1% of the population): less than 6 hours.

    • Elderly: around 6 hours; sleep amount often reflects disruptions rather than genuine reduced need.

    • New mothers may take years to revert to pre-pregnancy sleep levels.

Sleep Deprivation: Negative Consequences

  • Consequences of sleep deprivation can include:

    • Weight gain.

    • Depression.

    • Increased risk of cardiovascular problems.

    • Decreased immune function.

Alterations of Normal Consciousness

  • Sleep paralysis: Intense fear during REM muscle atonia.

  • Locked-In Syndrome: Full consciousness but complete paralysis; communication primarily through eye movements.

  • NDEs: Reported out-of-body sensations and associated with vivid dreams.

Stages of Sleep

  • Five cyclical stages of sleep occur approximately every 90 minutes.

  • Stages 1-4: Non-REM (NREM) sleep characterized by no eye movements and few dreams.

  • Stage 5: REM sleep with vivid dreams.

Stages VS Wakefulness

Brain Waves and Characteristics:

  • Awake: Beta waves; heightened alertness.

  • Calm Wakefulness: Alpha waves; relaxed state.

  • Stage I: 5-10 minutes; Theta waves; includes hypnagogic imagery and myoclonic jerks.

  • Stage II: Sleep spindles and K-complexes indicative of deeper sleep.

  • Stages III & IV: Delta waves indicate deep sleep crucial for feeling rested.

  • Stage V (REM): Similar brain activity as wakefulness; longer durations through the night and muscle atonia.

REM Facts

  • REM sleep is paradoxical due to brain activity amidst muscle paralysis.

  • REM Rebound: Increased tendency to enter REM sleep after deprivation.

  • The exact function of REM remains partially understood.

Polysomnography

  • Type I polysomnography involves overnight monitoring of physiological changes during sleep.

    • Monitors include EEG (brain activity), EOG (eye movements), EMG (muscle activity), ECG (heart rhythm), and respiratory functions.

Sleep Disorders

  • Affect up to 30-50% of the population, costing roughly $63 billion/year in the U.S.

  • Insomnia: 9-20% prevalence; challenges with sleep onset or maintenance; often co-occurs with depression and treated through therapy and medication.

  • Narcolepsy: Characterized by sudden sleep onset; cataplexy may occur; linked to low orexin levels.

  • Sleep Apnea: Airway blockages lead to disrupted sleep patterns.

  • Night Terrors: Common in children; characterized by confusion, terror, and back to sleep state.

  • Sleepwalking: Affects 15-30% of children and 3-5% of adults; safe to wake a sleepwalker.

Topic 5.2: Dreams

Why Do We Dream?

  • Reasons include:

    • Processing emotional memories.

    • Integrating new information.

    • Simulating threats for better coping.

    • Memory consolidation.

Types of Dreams

  • NREM Dreams: Characteristically shorter and more thought-like.

  • REM Dreams: Vivid, emotional, illogical content; contain plot shifts and bizarre narratives.

Lucid Dreaming

  • A state where the dreamer is aware they are dreaming, allowing for some narrative control; experienced by 20% of individuals.

Freud's Dream Protection Theory

  • Suggests dreams symbolically transform and represent repressed desires.

    • Respected division of manifest (surface) and latent (underlying) content. - Criticized for lack of empirical support.

Major Theories of Dreaming

  • Activation-Synthesis Theory (AST): Dreams interpret random neural activity during REM.

  • Neurocognitive Theory: Dreams evolve from cognitive development and life experiences, emphasizing continuity.

Topic 5.3: Alterations in Consciousness

Hallucinations and Experiences

  • Hallucinations: Realistic perceptions in the absence of stimuli; can occur during sensory deprivation or drug use.

    • Commonly reported by 10-35% of people.

    • OBEs and NDEs: Often consist of similar themes such as light, peace, and life reviews.

  • Déjà Vu: A common experience of feeling as if one has experienced something new before; often linked to temporal lobe activity.

Mystical Experiences

  • Defined as profound encounters that surpass normal perception and often relate to spirituality; induced through various means including meditation and substances.

Hypnosis

  • An interpersonal practice involving suggestive techniques for conscious alteration.

  • Common myths include its comparison to sleep, being a trance state, and amnesia which isn't typical.

Topic 5.4: Substance Use on Consciousness

Definitions and Explanations

  • Substance Abuse: Results in recurring problems related to the drug.

  • Dependence: Caused by tolerance, withdrawal symptoms.

Types of Psychoactive Drugs

  • Depressants: (e.g., alcohol, barbiturates) slow CNS activity leading to relaxation.

  • Stimulants: (e.g., caffeine, cocaine) increase CNS activity; users often report heightened energy and can lead to addiction.

  • Narcotics: (e.g., heroin) provide pain relief but are frequently misused.

  • Psychedelics: (e.g., LSD, marijuana) dramatically alter perception; potential cognitive impairment related to chronic use.

Conclusion

  • Substance use has profound implications for consciousness, leading to both psychological and physiological effects regularly discussed within the fields of psychology and health studies.