Psychology 2e Chapter 4 Notes

STATE OF CONSCIOUSNESS

WHAT IS CONSCIOUSNESS?

  • Definition of Consciousness: The awareness of internal and external stimuli, including feelings of hunger, pain, or the detection of light.
  • Wakefulness: Involves high levels of sensory awareness, thought, and behavior.
  • Visual Representation: Figure 4.1 shows an 1895 oil painting titled "Zwei schlafende Mädchen auf der Ofenbank" (Two Sleeping Girls on the Stove) by Albert Anker, illustrating the theme of sleep.

BIOLOGICAL RHYTHMS

  • Definition: A biological rhythm is an internal cycle of biological activity.
    • Includes fluctuations in body temperature.
    • Example: An individual's menstrual cycle.
    • Levels of alertness are also influenced by these rhythms.
  • Circadian Rhythm: A biological rhythm that occurs roughly over 24 hours, generated by the suprachiasmatic nucleus (SCN).
    • The sleep-wake cycle, a primary circadian rhythm, is closely linked to the natural light-dark cycles of our environment.
What Controls Our Biological Rhythms?
  • Hypothalamus Role: The hypothalamus plays a critical role in maintaining homeostasis, the balance or optimal level within a biological system.

CIRCADIAN RHYTHMS

  • Illustration of Body Temperature Change: A chart shows the circadian changes in body temperature over 28 hours in a group of eight young men, highlighting how body temperature rises during waking hours, peaking in the afternoon, and falls during sleep, reaching its lowest point in the early morning hours.

THE SUPRACHIASMATIC NUCLEUS (SCN)

  • Location and Function: The SCN is located in the hypothalamus and serves as the brain's timekeeping mechanism.
    • It sets itself based on light information received through projections from the retina, synchronizing it with the external environment.
MELATONIN AND SLEEP REGULATION
  • Role of Melatonin: The hormone melatonin regulates the sleep-wake cycle.
    • Release: Stimulated by darkness, promoting sleepiness, and inhibited by daylight.
  • Sleep Regulation: This involves the brain's ability to switch between sleep and wakefulness while coordinating with the external environment.
  • Chronotype: Each person has an individual circadian pattern of activity known as their chronotype.

DISRUPTIONS OF NORMAL SLEEP

  • Bright Light Devices: Tools designed to provide exposure to bright light that help individuals maintain a regular circadian cycle, particularly useful for night shift workers or those affected by seasonal light variations.
  • Jet Lag: Symptoms from the mismatch between internal circadian cycles and the external environment include:
    • Fatigue
    • Sluggishness
    • Irritability
    • Insomnia
  • Rotating Shift Work: Work schedules that change from early to late on a regular basis can complicate the maintenance of a normal circadian rhythm, leading to:
    • Persistent fatigue and agitation
    • Sleeping issues
    • Potential signs of depression and anxiety
  • Realigning Biological Clocks: Bright light therapy can be used to realign biological clocks with the external environment.

SLEEP DEPRIVATION

  • Consequences: Lack of sleep adversely affects multiple body systems, with cognitive deficits being one of the most apparent.
  • Sleep Debt: Refers to chronic insufficient sleep.
  • Sleep Rebound: A phenomenon where a sleep-deprived individual takes less time to fall asleep in subsequent opportunities for sleep.

SLEEP NEEDS AT DIFFERENT AGES

  • Recommended Sleep Hours: Varies by age; summarized below:
    • 0–3 months: 14–17 hours (appropriate range: 11–13 hours; not recommended:
    • 4–11 months: 12–15 hours (appropriate: 10–11 hours; not recommended:
    • 1–2 years: 11–14 hours (appropriate: 9–10 hours; not recommended:
    • 3–5 years: 10–13 hours (appropriate: 8–9 hours; not recommended:
    • 6–13 years: 9–11 hours (appropriate: 7–8 hours; not recommended:
    • 14–17 years: 8–10 hours (appropriate: 7 hours; not recommended:
    • 18–25 years: 7–9 hours (appropriate: 6 hours; not recommended:
    • 26–64 years: 7–9 hours (appropriate: 6 hours; not recommended:
    • ≥65 years: 7–8 hours (appropriate: 5–6 hours; not recommended:

WHAT IS SLEEP?

  • Definition: Sleep is a state marked by relatively low physical activity and a reduced sense of awareness.
  • Control: Sleep-wake cycles are controlled by multiple brain areas, including the thalamus and hypothalamus (for slow-wave sleep) and the pons (for REM sleep).
  • Hormonal Regulation During Sleep: Includes secretion and regulation of hormones such as melatonin, follicle stimulating hormone, luteinizing hormone, and growth hormone.

BRAIN AREAS INVOLVED IN SLEEP

  • Pineal and Pituitary Glands: These secrete several hormones during sleep.

WHY DO WE SLEEP?

  • Adaptive Function (Evolutionary Hypotheses):
    • Essential for restoring resources expended during the day.
    • An adaptive response to predatory risks that are exacerbated in the dark.
    • Limited evidence supports these explanations.
  • Cognitive Function:
    • Sleep is necessary for cognitive function and memory formation.
    • Sleep deprivation leads to cognitive disruptions and memory deficits that intensify with increased sleep deprivation.
    • Slow-wave sleep is crucial for effective memory formation.
  • Benefits of Sleep:
    • Maintaining a healthy weight
    • Lowering stress levels
    • Improving mood
    • Enhancing motor coordination
    • Supporting cognition and memory formation.

BRAINWAVES DURING SLEEP

  • Changes in brainwave activity are observed across different stages of sleep, visualized using EEG:
    • Alpha Waves: Low frequency, high amplitude, synchronized.
    • Theta Waves: Low frequency, low amplitude.
    • Delta Waves: Low frequency, high amplitude, desynchronized.
STAGES OF SLEEP

  • Stages 1 and 2:

    • Stage 1:
    • Transitional phase between wakefulness and sleep.
    • Heartbeat and respiration slow.
    • Muscle tension and core body temperature decrease.
    • Typical brainwaves: Alpha waves.
    • Stage 2:
    • Deep relaxation is reached.
    • Characterized by the appearance of theta waves, sleep spindles (rapid bursts of high-frequency brainwaves), and K-complexes (very high amplitude brain activity).

  • Stages 3 and 4:

    • Both stages involve delta waves and are known collectively as slow-wave sleep.
    • Additional slowing of respiration and heart rate.
RAPID EYE MOVEMENT (REM) SLEEP
  • Characteristics:
    • Marked by rapid eye movements.
    • Paralysis of voluntary muscles.
    • Typically associated with dreams.
    • Brain waves during REM sleep resemble those seen during wakefulness.
HYPNOGRAM OF SLEEP STAGES
  • Definition: A hypnogram is a diagram representing the stages of sleep throughout a sleep period, detailing how an individual transitions through various stages.

DREAMS

  • Theoretical Perspectives:
    • Sigmund Freud: Believed dreams provide access to the unconscious mind.
    • Manifest Content: The actual content of the dream.
    • Latent Content: The hidden meaning of the dream.
    • Carl Jung: Offered the theory that dreams tap into the collective unconscious, representing universal archetypes.
  • Research Findings: Dreams might reflect significant life events for the dreamer and may serve as a state of protoconsciousness that aids cognitive processes.
  • Lucid Dreams: A state in which individuals recognize they are dreaming and can sometimes exert control over the dream.

INSOMNIA

  • Definition: Characterized by difficulty in falling or staying asleep at least three nights a week for over a month; it's the most common sleep disorder.
    • Can be linked with symptoms of depression.
  • Contributing Factors:
    • Age
    • Drug use
    • Exercise patterns
    • Mental health status
    • Poor bedtime routines
  • Treatment Options:
    • Stress management techniques.
    • Modifications in behaviors contributing to insomnia.
    • Cognitive-behavioral therapy addressing both cognitive processes and problematic behaviors.

PARASOMNIA

  • Definition: Involves unwanted motor behaviors or experiences throughout the sleep cycle.
  • Examples:
    • Sleep Walking: Usually occurs during slow-wave sleep.
    • REM Sleep Behavior Disorder: Lack of muscle paralysis during REM results in high levels of activity during dreams; may be treated with Clonazepam (an anti-anxiety medication).
    • Restless Leg Syndrome: Characterized by uncomfortable sensations in the legs, relieved by movement; treatment with various medications.
    • Night Terrors: Occur during NREM sleep, marked by feelings of panic; the sleeper may scream or attempt to escape.

SLEEP APNEA

  • Definition: A condition where breathing stops during sleep for periods of 10-20 seconds or longer, leading to increased fatigue.
  • Commonality: Particularly frequent in overweight individuals.
  • Types:
    • Obstructive: Airway blockage prevents airflow.
    • Central: Central nervous system fails to initiate breathing.
  • Treatment Options: Continuous Positive Airway Pressure (CPAP) devices that deliver air into airways.

SUDDEN INFANT DEATH SYNDROME (SIDS)

  • Definition: Occurs when an infant stops breathing during sleep; this is particularly risky for infants under 12 months and boys are at greater risk than girls.
  • Contributing Factors:
    • Premature birth
    • Exposure to smoking in the home
    • Hyperthermia
  • Prevention Campaign: The Safe to Sleep campaign, supported by the National Institute of Child Health and Human Development, aims to reduce risk factors associated with SIDS.

NARCOLEPSY

  • Definition: Involves an uncontrollable urge to sleep during waking hours, often triggered by heightened arousal or stress.
  • Features:
    • Cataplexy: Sudden loss of muscle tone while awake.
    • Hypnagogic Hallucinations: Vivid, dream-like hallucinations occur at sleep onset.
  • Treatment Strategies: Often managed with psychomotor stimulant medications.

SUBSTANCE USE DISORDERS

  • Definition: A compulsive pattern of drug usage despite adverse consequences as defined by the DSM-5.
  • Involves:
    • Physical Dependence: Changes in normal body functions and withdrawal symptoms upon cessation of use.
    • Psychological Dependence: An emotional need for the substance.
  • Tolerance: Occurs when increasing amounts of a substance are needed to achieve effects initially felt at lower doses, often linked to physical dependence.
  • Withdrawal: Refers to negative symptoms experienced when stopping drug use.

DRUG CATEGORIES

  • Drugs and Their Effects:
    • Stimulants: e.g., Cocaine, amphetamines
    • Effects: Increased heart rate, blood pressure, heightened alertness, potential for agitation and paranoia.
    • Psychological Addictiveness: Yes.
    • Sedative-Hypnotics (Depressants): e.g., Alcohol, Benzodiazepines
    • Effects: Decreased heart rate, relaxation, high doses can induce sleep and cause respiratory issues.
    • Psychological Addictiveness: Yes.
    • Opiates: e.g., Heroin, Morphine
    • Effects: Pain relief, decreased respiration, euphoria.
    • Psychological Addictiveness: Yes.
    • Hallucinogens: e.g., LSD, DMT
    • Effects: Altered sensory perceptions, variable effects based on strain and ingestion methods.
    • Psychological Addictiveness: Yes.
DEPRESSANTS
  • Mechanism: Suppress CNS activity, typically GABA agonists leading to a quieting effect on the brain.
    • Examples: Alcohol reduces reaction time, decreases alertness, and can lead to unconsciousness.
STIMULANTS
  • Mechanism: Increase neural activity, often dopamine agonists preventing reuptake of dopamine.
    • Side Effects: Nausea, anxiety, hallucinations.
DOPAMINE AGONISTS
  • Mechanism: Block reuptake of dopamine leading to greater amounts present in the synapse.
NICOTINE AND CAFFEINE
  • Nicotine: Interacts with acetylcholine receptors and is highly addictive, tied with arousal and reward.
  • Caffeine: Antagonizes adenosine activity, heightening alertness and arousal.
OPIOIDS
  • Efficacy: Serve as analgesics, deeply affecting the endogenous opioid neurotransmitter system; highly addictive.
HALLUCINOGENS
  • Effects: Alter sensory experiences, can include intense hallucinations, affecting various neurotransmitter systems.