Consciousness, Biological Rhythms, and Drugs

Consciousness

  • The brain generates conscious awareness, a unique property not found in other matter.
  • Descartes viewed the mind as separate but connected to the body.
  • William James described consciousness as a continually changing stream of mental activity.
  • Freud focused on the subconscious aspects of this stream.
  • Consciousness involves awareness of internal and external stimuli, personal awareness (e.g., "The professor just asked me a question about consciousness"), awareness of self as a unique being (e.g., "Why me?"), and awareness of thoughts and feelings (e.g., "I am going to make a fool of myself!").
  • Consciousness is defined as personal awareness.

The Nature of Consciousness

  • The question is posed whether consciousness is unitary, fixed, and universal, or distributed, variable, and special.
  • Definitions of consciousness vary.

Consciousness and Animals

  • Thought experiment: If humans, as products of evolution, possess conscious awareness, what about other species?
  • The Cambridge Declaration on Consciousness (July 7, 2012) was a proclamation by a group of cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists, and computational neuroscientists.
  • The declaration supports the idea that animals (including all mammals, birds, and even octopuses) are conscious and aware to the same degree as humans.
  • Raises ethical questions about the treatment of animals.

Machine Consciousness

  • Considers the possibility of machines becoming conscious.

Blindsight

  • Blindsight (Weiskrantz, 1986) demonstrates visual capacities in scotoma.
  • Patient D.B., who had part of his visual cortex removed, had a scotoma.
  • Weiskrantz found that D.B. could 'guess' the orientation of a stick, point to a target, and reach for an outstretched hand, indicating he could 'see' things he was not aware of.

Visual Spatial Neglect

  • Caused by damage to the Parietal Lobe.
  • Impairs the ability to attend to the side of space opposite the damaged hemisphere.
  • Vision is normal, but attention is impaired.
  • Example: a patient only eats food from the side of the plate corresponding to the undamaged hemisphere.

Biological Rhythms

  • Types of biological rhythms:
    • Circadian: approximately 24 hours, entrained by the revolution of the Earth.
    • Circatidal: approximately 12.4 hours, entrained by tides.
    • Circalunar: approximately 29.5 days, entrained by phases of the moon.
    • Circannual: approximately 365.25 days, entrained by seasons of the year.
    • Free-running circadian: 22-26 hours.
    • Free-running circatidal: 11-14 hours.
    • Free-running circalunar: 26-32 days.
    • Free-running circannual: 330-400 days.

Circadian Rhythms

  • Any rhythmic change that continues at close to a 24-hour cycle in the absence of 24-hour cues, including body temperature, cortisol secretion, and sleep/wakefulness.
  • Infradian rhythms occur less than once a day.
  • Ultradian rhythms occur more than once a day.
  • In the absence of time cues, the cycle period becomes somewhat longer than 24 hours.

Daily Rhythms

  • Body temperature, systolic blood pressure, and cortisol hormone secretion fluctuate throughout the day.

Examples of Human Circadian Rhythms

  • Peak mental alertness and memory functions: around 9 AM and 9 PM.
  • Lowest body temperature: around 3 to 4 AM (approximately 36.236.2 degrees Celsius).
  • Highest body temperature: around 5 to 6 PM (approximately 37.237.2 degrees Celsius).
  • Peak physical strength: around 11 AM and 7 PM.
  • Peak hearing, visual, taste, and smell sensitivity: around 3 AM and 6 PM.
  • Lowest sensitivity to pain: around 3 to 5 PM.
  • Peak sensitivity to pain: around 3 to 5 AM.
  • Peak degree of sleepiness: around 3 AM and 3 PM.
  • Peak melatonin hormone in blood: between 1 and 3 AM.

Isolation Studies

  • Jurgen Aschoff in Germany conducted isolation experiments.
  • Subjects were placed in an underground bunker and allowed to control lights.
  • Aschoff tracked sleep-wake cycles, body temperature, and other variables.
  • He concluded that humans have endogenous circadian cycles.
  • Humans show free-running rhythms with periods of approximately 25 hours.
  • Siffre (1972), a speleologist, lived in a cave for 7 months without time cues and mentally lost 25 days.

Actogram

  • Actogram: a graph of activity patterns.
    • White represents active periods.
    • Black represents inactive periods.
  • Demonstrates free-running rhythms when time cues are absent.

Zeitgebers and Body Clocks

  • Internal clocks require time cues (light) to reset them.
  • Zeitgebers are time cues, external or environmental cues that entrain biological rhythms.

EEG: Physiological Index of Consciousness

  • Electroencephalogram: monitoring of brain electrical activity.
  • Brain-waves: amplitude (height) and frequency (cycles per second).
    • Beta (13−2413-24 cps): normal waking thought, problem-solving.
    • Alpha (8−128-12 cps): deep relaxation, blank mind, meditation.
    • Theta (4−74-7 cps): light sleep, deep sleep.
    • Delta (<4 cps): deepest sleep.

The Body’s Clock and Sleep

  • Regulation of sleep/other body functions.
  • Physiological pathway of the biological clock: Light levels -> retina -> suprachiasmatic nucleus (SCN) of hypothalamus -> pineal gland -> secretion of melatonin.
  • Suprachiasmatic nucleus (SCN): a cluster of neurons in the hypothalamus that governs the timing of circadian rhythms.
  • Melatonin: a hormone of the pineal gland that produces sleepiness.
  • Bright light decreases melatonin production; decreased light increases melatonin.

Sleep Stages

  • Stage 1: brief, transitional (1-7 min.) - alpha > theta - hypnic jerks.
  • Stage 2: sleep spindles (10-25 min.).
  • Stages 3 & 4: slow-wave sleep (30 min.).
  • Stage 5: REM (rapid eye movement), EEG similar to awake, vivid dreaming, REM atonia (initially a few minutes, progressively longer as cycle through the stages).
  • Developmental differences exist in REM sleep.

Sleep Cycles

  • Illustrates shifts in posture and eye movements across sleep stages.

Sleep Architecture

  • Shows the progression through sleep stages (Awake, NREM stages 1-4, and REM) over hours of sleep.
  • REM periods become more frequent and longer throughout the night.

Functions of Sleep

  • Restoration theory (biological perspective): the body wears out during the day, and sleep is necessary to restore it.
  • Adaptive theory (evolutionary perspective): sleep emerged to preserve energy and protect during times of day with considerable danger.
  • Consolidation of memory.

Sleep Deprivation

  • The metabolism in the prefrontal and parietal association areas of the brain decreases after 24 hours of sleep deprivation.
  • These brain areas are important for judgment, impulse control, attention, and visual association.
  • Microsleep: episodes lasting only a few seconds.
  • REM rebound: deprivation of REM sleep causes an increase in time spent in REM sleep to “catch up.”
  • NREM rebound: catching up on Stages 3 and 4 sleep.

Lark or Owl?

  • There are 'morning' people and 'night' people.
  • Period 3 gene influences this preference; a long gene is associated with being an early riser, and a short gene with being a late riser.
  • Behavior can override genetics.

Individual Differences in Sleep Drive

  • Some individuals need more or less than the typical 8 hours of sleep per night.
  • Nonsomniacs: sleep far less than most but do not feel tired during the day.
  • Insomniacs: have a normal desire for sleep but are unable to sleep and feel tired during the day.

Sleep Problems

  • Insomnia: difficulty falling or staying asleep.
  • Narcolepsy: falling asleep uncontrollably.
  • Sleep Apnea: reflexive gasping for air that awakens the sleeper.
  • Nightmares: anxiety-arousing dreams during REM sleep.
  • Night Terrors: intense arousal and panic during NREM sleep.
  • Somnambulism: sleepwalking.
  • Lack of Dreams: may be related to parietal lobe injury.

Incidence of Sleep Disorders by Stage

  • Indicates the timing of sleepwalking, night terrors, and nightmares in relation to sleep stages.

Dreams and REM Sleep

  • True dream: vivid, detailed dreams consisting of sensory and motor sensations experienced during REM and NREM sleep.
  • Sleep thinking: lacks vivid sensory and motor sensations, more similar to daytime thinking, and occurs during slow-wave sleep.

Significance of Dreams

  • Psychoanalytic Interpretation: dreams as “wish fulfillments.”
    • Manifest content: elements of the dream that are consciously experienced and remembered.
    • Latent content: the unconscious wishes that are concealed in the manifest content.
  • Activation Synthesis Model: brain activity during sleep produces dream images (activation), which are combined by the brain into a dream story (synthesis).
  • Dreams have a problem-solving function.

Hypnosis

  • Hypnosis: a systematic procedure that increases suggestibility.
  • State of awareness characterized by:
    • Highly focused attention.
    • Increased responsiveness to suggestion.
    • Vivid imagery.
    • Willingness to accept distortions of logic.
    • Alteration of sensation and perception.

Drug Addiction Potential

  • A ranking of various drugs according to their inherent addictive potential, based on a composite ranking of each drug on a 100100-point scale from least to most addictive-liable.

Drugs: Use and Abuse

  • Drug addiction emerged in the US with the use of morphine (from opium) in Civil War soldiers (known as Soldier’s disease), aside from alcohol and nicotine use.
  • Many drugs of abuse originated in plants (e.g., nicotine, cocaine, opium); the rest were made by drug companies.
  • Until 1906, all drugs were legal; most remained legal for many years.

Legal Drug Manufacturing

  • Lists major pharmaceutical companies (Johnson & Johnson, Roche, Pfizer, Merck & Co.) with their revenue, profit, and number of employees.
  • Provides comparison data for Walmart, Amazon, and Apple.

The Impact of Drugs

  • Drugs production, smuggling and distribution have exploded into sophisticated multinational business structure, estimated at 426−652426-652 billion annually worldwide.

Deaths Attributed to substance use in Canada

  • Substance use contributes to approximately 67,00067,000 deaths annually in Canada, including over 47,00047,000 from tobacco and nearly 15,00015,000 from alcohol.

What is Drug Abuse?

  • The use of any drug