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States of Consciousness

WHAT IS CONSCIOUSNESS?

  • Consciousness = awareness of internal and external stimuli (e.g., feelings of hunger and pain) or detection of light.

  • Wakefulness = high levels of sensory awareness, thought, and behavior.

  • Other states of consciousness include:

    • sleep

    • daydreaming

    • intoxication

    • unconsciousness

    • altered states (drugs, meditation, hypnosis)

  • Visual cue: reference to art (Two sleeping children) to illustrate everyday experience of consciousness.

BIOLOGICAL RHYTHMS

  • Biological rhythm = internal cycle of biological activity, e.g., fluctuations in body temperature, menstrual cycle, levels of alertness.

  • Circadian rhythm = ~24-hour biological rhythm (e.g., sleep-wake cycle, heart rate).

    • Generated by the suprachiasmatic nucleus (SCN).

    • Sleep-wake cycle is linked to the environment's light-dark cycle.

  • What controls biological rhythms?

    • The hypothalamus maintains homeostasis within a biological system.

CIRCADIAN RHYTHMS

  • This circadian pattern can be observed as body temperature fluctuating over a ~28-hour cycle in a small sample (eight young men):

    • Temperature rises during waking hours, peaks in the afternoon, falls during sleep, with the lowest point in the very early morning.

THE SUPRACHIASMATIC NUCLEUS (SCN)

  • SCN = brain’s clock mechanism, located in the hypothalamus.

  • Mnemonic: think “C” in ‘Chiasm’ stands for Clock.

  • Clock setting: adjusted by light information received through projections from the retina to synchronize with the outside world.

WHAT IS SLEEP & WHY DO WE SLEEP?

  • Sleep is a state of relatively low physical activity and reduced awareness.

  • Brain areas involved in sleep regulation:

    • thalamus & hypothalamus (slow-wave sleep)

    • pons (REM sleep)

  • Sleep regulation = brain’s control of switching between sleep and wakefulness and coordinating this cycle with the outside world.

  • Each person has an individual circadian pattern, i.e., a chronotype.

  • Melatonin (discussed next) can influence sleep disorders related to production/release.

MELATONIN AND SLEEP REGULATION

  • Melatonin release is stimulated by darkness (promotes sleep) and inhibited by daylight.

  • Melatonin is released by the pineal gland.

  • Sleep regulation = coordination of sleep-wake with environmental cues.

  • Chronotype = individual circadian pattern of activity.

  • Sleep disorders may be related to melatonin production/release.

DISRUPTIONS OF NORMAL SLEEP

  • Bright-light exposure devices help maintain a regular circadian cycle (useful for night-shift workers or seasonal light changes).

  • Jet lag = mismatch between internal circadian cycles and environment; symptoms include fatigue, sluggishness, irritability, insomnia.

  • Rotating shift work = schedule changes from early to late; can disrupt normal circadian rhythm, causing fatigue, sleep problems, and mood disturbances.

  • Tips to realign circadian rhythms: use bright light exposure to shift the clock toward the environment.

  • Figure references (e.g., Figure 4.4) indicate illustrative examples.

SLEEP DEPRIVATION

  • Consequences of insufficient sleep span cognitive deficits and other body systems.

  • Sleep debt = chronic sleep insufficiency.

  • Sleep rebound = when sleep-deprived, faster sleep onset on subsequent opportunities to sleep.

  • Don’t forget to assess your own sleep needs (e.g., via Sleep Foundation).

SLEEP NEEDS

  • Sleep needs vary by age. Typical recommendations and boundaries (examples):

    • 0–3 months: 14-17 hours (Recommended); 11-13 hours (May be appropriate); 18-19 hours (Not recommended); Fewer than 11 hours; More than 19 hours

    • 4–11 months: 12-15 hours (Recommended); 10-11 hours (May be appropriate); 16-18 hours (Not recommended); Fewer than 10 hours; More than 18 hours

    • 1–2 years: 11-14 hours (Recommended); 9-10 hours (May be appropriate); 15-16 hours (Not recommended); Fewer than 9 hours; More than 16 hours

    • 3–5 years: 10-13 hours (Recommended); 8-9 hours (May be appropriate); 14 hours (Not recommended); Fewer than 8 hours; More than 14 hours

    • 6–13 years: 9-11 hours (Recommended); 7-8 hours (May be appropriate); 12 hours (Not recommended); Fewer than 7 hours; More than 12 hours

    • 14–17 years: 8-10 hours (Recommended); 7 hours (May be appropriate); 11 hours (Not recommended); Fewer than 7 hours; More than 11 hours

    • 18–25 years: 7-9 hours (Recommended); 6 hours (May be appropriate); 10-11 hours (Not recommended); Fewer than 6 hours; More than 11 hours

    • 26–64 years: 7-9 hours (Recommended); 6 hours (May be appropriate); 10 hours (Not recommended); Fewer than 6 hours; More than 10 hours

    • ≥65 years: 7-8 hours (Recommended); 5-6 hours (May be appropriate); 9 hours (Not recommended); Fewer than 5 hours; More than 9 hours

  • Question: "Do we really need 8 hours of sleep? How do we know how much sleep we each need?" (prompts reflection on personal sleep needs)

WHAT IS SLEEP? (DETAILED)

  • Sleep definition reiterated: state with low activity and reduced awareness.

  • Brain regions involved in sleep stages:

    • Thalamus & Hypothalamus = slow-wave sleep

    • Pons = REM sleep

  • Sleep is associated with secretion/regulation of various hormones, including:

    • Melatonin

    • Follicle-stimulating hormone (FSH)

    • Luteinizing hormone (LH)

    • Growth hormone

WHY DO WE SLEEP? (ADAPTIVE FUNCTION)

  • Evolutionary hypotheses (one perspective):

    • Sleep may restore resources expended during the day.

    • Sleep may be an adaptive response to predation risk in darkness.

    • Evidence for these explanations is limited.

  • Research emphasizes sleep’s importance for cognitive function and memory.

  • Benefits of sleep (6 tips):

    1. Maintaining a healthy weight

    2. Lowering stress levels

    3. Improving mood

    4. Increased motor coordination

    5. Cognition

    6. Memory formation

WHY DO WE SLEEP? (COGNITIVE FUNCTION)

  • Sleep deprivation leads to disruptions in cognition and memory; effects worsen as deprivation increases.

  • Slow-wave sleep appears essential for effective memory formation.

ACTIVITY: CONSCIOUSNESS & ATTENTION

  • While watching a video, focus on a team wearing white and count the passes; answer is recorded later (example activity to illustrate attention).

CONSCIOUSNESS & ATTENTION - FUN EXERCISE

  • Inattentional blindness: not noticing things in periphery when focused on something else (e.g., being on the phone while walking).

  • Experimental observation: only ~25% of people on their phones noticed a clown on a unicycle in a busy campus area.

WHAT ARE THE STAGES OF SLEEP?

  • Overview of sleep stages with characteristic brain activity patterns (EEG).

  • Brainwave types referenced:

    • Alpha: relatively low frequency, relatively high amplitude, synchronized (awake/relaxed).

    • Theta: low frequency, low amplitude.

    • Delta: low frequency, high amplitude.

    • Beta: relatively low frequency, awake state.

BRAINWAVES DURING SLEEP

  • EEG visualizes changes across stages:

    • Alpha waves prominent during relaxed wakefulness.

    • Theta waves appear in early sleep.

    • Delta waves dominate slow-wave sleep (Stages 3 & 4).

    • REM sleep shows wake-like brain activity (beta-range) but with muscle atonia.

STAGES 1 AND 2

  • STAGE 2:

    • Deep relaxation; dominated by Theta waves.

    • Features: Sleep spindles (rapid bursts of high-frequency waves) and K-complexes (very high amplitude patterns).

  • STAGE 1:

    • Transitional phase between wakefulness and sleep.

    • Physiological changes: slower respiration and heartbeat; decrease in core body temperature and muscle tension.

    • Predominant EEG: Alpha waves.

STAGES 3 AND 4

  • Known as slow-wave sleep or deep sleep (Stage 3 and Stage 4):

    • Delta waves dominate.

    • Further reduction in respiration and heart rate.

REM SLEEP

  • Rapid Eye Movement (REM):

    • Rapid eye movements occur.

    • Voluntary muscles are paralyzed (atonia).

    • Dreams commonly occur.

    • Brain waves resemble wakefulness (often Beta range).

HYPNOGRAM OF SLEEP STAGES

  • A hypnogram charts the progression of sleep stages across a sleep period.

  • It illustrates how an individual cycles through stages (Wake → Stage 1 → Stage 2 → Stage 3/4 → REM, and repeats).

DREAMS

  • Theories on dream meaning vary by culture and era:

    • Sigmund Freud: dreams reveal the unconscious.

    • Manifest content: the actual content of the dream.

    • Latent content: the hidden meaning behind the dream.

    • Carl Jung: dreams access the collective unconscious, a repository of shared human information across cultures.

    • Symbols in dreams may reflect universal archetypes.

    • Research findings:

    • Dreams may represent life events important to the dreamer.

    • Dreaming may reflect protoconsciousness or a virtual reality in the mind aiding consciousness.

    • Lucid dreams: the dreamer becomes aware they are dreaming while dreaming.

DREAMS (RECAP/ELABORATION)

  • Recap of Freud, Jung, and research perspectives:

    • Manifest content vs latent content (Freud).

    • Collective unconscious and archetypes (Jung).

    • Protoconsciousness and dream utility during consciousness.

    • Lucid dreaming as a state where aspects of wakefulness persist during dreaming.

DREAM EXAMPLE (PRACTICE QUESTION)

  • Example: Don has a dream about being booed off stage during an impromptu stand-up routine. His friend AJ suggests the dream reflects his nervousness about the upcoming graduation speech.

  • The analysis focuses on:

    • A) the important content of the dream

    • B) the collective unconscious

    • C) the manifest content of the dream

    • D) the latent content of the dream

  • Correct answer: D) the latent content of the dream (hidden meaning).