Psychology chapter 13-14 : Consciousness Overview

Consciousness

• An individual's awareness of their surroundings and themselves
• Examples of altered states of consciousness: sleep and dreaming
• Reticular Activating System (RAS): Responsible for alertness and wakefulness. Found within the brainstem. Damage to the RAS can induce sleep or coma.
• Dissociation: Separation of certain thoughts, behaviors, or memories from consciousness. Can be mild (e.g., driving while lost in thought) or severe (e.g., psychological disorders affecting memory and identity)
• Introspection: Observing and reporting conscious thoughts and sensations (used by Wilhelm Wundt to study consciousness)
• William James: Described consciousness as a continuous and ever-changing "stream of thought"
• Sigmund Freud proposed three levels of consciousness:
  • Unconscious: Totally beyond conscious awareness
  • Preconscious: Just below conscious awareness
  • Conscious: Our current awareness
• Personality: Freud believed personality arises from conflicts between the conscious and unconscious mind (e.g., desires vs. morality).

Sleep

• A state of altered consciousness beyond normal wakefulness
• Pons: Brainstem area critical to sleep regulation. Also plays a role in dreaming.
• Activation-Synthesis Hypothesis: Dreams are the brain's attempt to interpret the random activity of the pons during sleep.

Sleep Stages and Cycles

• Non-Rapid Eye Movement (NREM) Sleep: Stages N1-3, characterized by slower brain activity and decreased bodily functions
• Rapid Eye Movement (REM) Sleep: Characterized by brain activity resembling an alert state (high-frequency, low-amplitude waves), rapid eye movements, and muscle relaxation (except for eye and respiratory muscles). Most dreaming occurs during REM sleep
• Sleep Cycles: Occur in 90-minute intervals throughout the night, with increasing REM sleep as the night progresses.
• Electroencephalography (EEG): Recording brain electrical activity during sleep and waking states
• Brain Wave Patterns:
  • Beta Waves: High frequency, typical of wakefulness and alertness.
  • Alpha Waves: More regular than beta waves, associated with a relaxed, awake state.
  • Theta Waves: Characteristic of Stage 1 sleep (N1), also known as light sleep.
  • Sleep Spindles: Short bursts of high-frequency activity during Stage 2 NREM sleep.
  • K-Complexes: High-amplitude brain waves during Stage 2 NREM sleep.
  • Delta Waves: Slowest frequency and highest amplitude waves, typical of Stage 3 sleep (N3), the deepest stage of NREM sleep.
• Sleep Deprivation: Results in fatigue, difficulty concentrating, depression, and weight gain.
• REM Rebound Effect: Individuals deprived of REM sleep experience an increase in REM sleep the following night, resulting in more vivid and prolonged dreams.

Circadian Rhythms

• 24-hour cycles in physiological activity and behavior (e.g., hormone release, sleep-wake cycle)
• Suprachiasmatic Nucleus (SCN): Located in the hypothalamus, it regulates circadian rhythms.
• Pineal Gland: A gland responsible for melatonin production.
• Melatonin: A hormone that promotes sleepiness. Released by the pineal gland when it is dark.
• Light Levels: Photoreceptors in the retina send information about light levels to the SCN, regulating melatonin release.

Dreaming

• Primarily associated with REM sleep, particularly later REM cycles.
• Cognitive Problem-Solving Theory: Dreams provide opportunities for the brain to work through problems encountered during wakefulness.
• Wish Fulfillment (Freud): Dreams represent a way to satisfy urges or desires that are unacceptable during waking hours (manifest content masks latent content).
• Pons: Plays a role in the activation-synthesis hypothesis of dreaming

Sleep-Wake Disorders

• Conditions marked by disturbed sleep that cause distress or impaired functioning.
• Dyssomnias: Disturbances in sleep quality.
• Parasomnias: Abnormal nervous system function during sleep.
• Examples of Dyssomnias:
  • Narcolepsy: Sudden, uncontrollable episodes of sleep, often triggered by strong emotions.
  • Insomnia: Difficulty falling asleep or staying asleep.
  • Sleep Apnea: Disrupted sleep due to repeated cessation of breathing, leading to brief awakenings. Symptoms include snoring, gasping for air, and daytime fatigue.
• Examples of Parasomnias:
  • Somnambulism: Sleepwalking, most common in children.
  • Night Terrors: Episodes of screaming, crying, or panic during sleep, usually during NREM sleep and not remembered.

Consciousness-Altering Substances

• Substances that affect mood, perception, thinking, and/or behavior.
• Psychoactive Drug Categories:
  • Stimulants: Increase CNS activity, causing elevated heart rate and feelings of well-being, energy, and alertness (e.g., cocaine, nicotine, caffeine).
  • Depressants: Decrease CNS activity, causing drowsiness, impaired coordination, and reduced behavioral inhibition (e.g., alcohol, benzodiazepines, barbiturates).
  • Opioids: Mimic endorphins, causing pain relief and relaxation (e.g., morphine, heroin). Can lead to increased pain and dependence after prolonged use.
  • Hallucinogens: Cause distortions in perception in the absence of sensory input (e.g., LSD, psilocybin, mescaline). Have the lowest risk of dependence among psychoactive drug categories.
• Marijuana & MDMA: Have effects that cross multiple drug categories (e.g., stimulant and hallucinogen).

Problematic Substance Use

• Long-term use of psychoactive substances can lead to physiological and psychological dependence.

Consciousness

• Consciousness is defined as an individual's awareness of their environment and themselves.
• Altered states of consciousness, like sleep and dreaming, differ from normal alertness.
• The reticular activating system (RAS) within the reticular formation is crucial for consciousness and wakefulness. Damage to the RAS can lead to sleep or a coma.
• Dissociation, the separation of thoughts, behaviors, or memories from normal consciousness, can occur in mild cases like being lost in thought while driving. Severe dissociation can be a characteristic of psychological disorders.
• Wilhelm Wundt believed that introspection, the process of observing and reporting conscious thoughts and sensations, could reveal the elements of consciousness.
• William James believed that consciousness is a continuous and ever-changing "stream of thought."
• Sigmund Freud proposed three levels of consciousness: unconscious, preconscious, and conscious. His theory suggests personality arises from conflicts between the conscious and unconscious mind.

Sleep

• Sleep is an altered state of consciousness characterized by reduced wakefulness.
• Brain regions in the pons play a significant role in regulating sleep.
• The activation-synthesis hypothesis posits that dreams result from the brain's attempt to interpret random neural activity in the pons during sleep.

Stages of Sleep

• Sleep cycles are divided into non-rapid eye movement (NREM) sleep (stages N1-3) and rapid eye movement (REM) sleep.
• A typical night's sleep consists of 4-6 90-minute cycles, with the proportion of REM sleep increasing with each cycle.
• REM sleep accounts for 20%-25% of total sleep time for adults.
• Electroencephalography (EEG) records brain wave patterns that reflect states of wakefulness and sleep.
• Beta waves, the highest frequency waves, characterize an awake and alert state. Alpha waves are more regular and indicate an awake, relaxed state.
• Stage 1 NREM sleep (N1 or "light sleep") is marked by theta waves and characterized by sudden jerking movements as the person falls asleep.
• Stage 2 NREM sleep (N2) is associated with theta waves interspersed with sleep spindles and K-complexes.
• Stage 3 NREM sleep (N3 or "slow-wave sleep") is the deepest stage and characterized by delta waves, which are the lowest frequency and highest amplitude waves.
• REM sleep is characterized by brain activity similar to wakefulness, featuring high-frequency, low-amplitude waves.
• REM sleep is also known as paradoxical sleep because of the paradoxical combination of brain activity resembling wakefulness and a relaxed body.
• Muscle tone in the body is significantly reduced during REM sleep, preventing the acting out of dreams.
• Sleep deprivation can lead to fatigue, depression, concentration difficulties, and weight gain.
• The REM rebound effect describes the increased amount of REM sleep experienced after a night of REM sleep deprivation, leading to more vivid and longer dreams.

Circadian Rhythms

• Circadian rhythms are 24-hour cycles in physiological activity (e.g., hormone release) or behavior (e.g., sleeping).
• The sleep-wake cycle is an example of a circadian rhythm.
• The suprachiasmatic nucleus (SCN) in the hypothalamus and the pineal gland regulate circadian rhythms.
• The SCN receives information about light levels from photoreceptors in the retina.
• In darkness, the SCN triggers the pineal gland to release melatonin, a hormone that induces sleepiness.
• When light levels are high, the SCN decreases melatonin production.
• Most circadian rhythms, including blood pressure and core body temperature, are synchronized with the sleep-wake cycle through melatonin secretion.

Dreaming

• Dreaming is most commonly associated with REM sleep, particularly the REM cycles that occur closer to waking.
• Dreaming can also occur during NREM sleep, though it is less common.
• The activation-synthesis hypothesis proposes that dreams arise from the brain's attempt to make sense of random neural activity in the pons during sleep.

Consciousness-Altering Substances

• Psychoactive drugs or substances affect mood, perception, thinking, and behavior.
• Categories of psychoactive drugs include stimulants, depressants, and hallucinogens.

Stimulants

• Stimulants increase CNS activity, leading to increased heart rate and feelings of well-being, energy, and alertness.
• Examples include cocaine, nicotine, caffeine, and amphetamines.

Depressants

• Depressants decrease CNS activity, leading to drowsiness, impaired coordination, and reduced behavioral inhibition.
• Include alcohol and sedatives like benzodiazepines and barbiturates.
• Enhance the effects of GABA, the brain's primary inhibitory neurotransmitter.

Opioids

• Opioids, like morphine and heroin, lessen pain and induce a relaxed state by mimicking the actions of endorphins.
• Long-term opioid use can lead to a decrease in the body's natural endorphin production, resulting in increased pain in the absence of the drug.

Hallucinogens

• Hallucinogens cause distortions in perception without sensory input, such as experiencing images that are not present in reality.
• Examples include LSD, psilocybin, and mescaline.
• Hallucinogens have the lowest risk of dependence compared to other categories of psychoactive drugs.

Problematic Substance Use

• Psychoactive drugs can lead to psychological and physical dependence.
• Psychological dependence involves the belief that the substance is essential for daily functioning.
• Physical dependence signifies the body's reliance on the substance, reflected in tolerance and withdrawal.
• Tolerance occurs when increasing doses of a substance are needed to achieve the initial effects.
• Withdrawal involves experiencing physical and/or psychological symptoms upon stopping chronic substance use.
• Substance use disorders are characterized by continued substance use despite significant negative consequences, such as health problems or functional impairments.
• Symptoms of substance use disorders include:
  • Unsuccessful attempts to cut back or stop using the substance
  • Intense cravings for the substance
  • Significant time spent on substance-related activities (e.g., obtaining or using the substance)
  • Tolerance
  • Withdrawal
• The mesolimbic reward pathway, containing dopaminergic neurons in the ventral tegmental area (VTA) that project to the nucleus accumbens, plays a crucial role in problematic substance use.
• This pathway is activated by rewarding stimuli, releasing dopamine and reinforcing behaviors that lead to reward.
• Drugs associated with substance-related disorders enhance the activity of these dopaminergic neurons, contributing to the reinforcement of drug use.
• Blocking dopamine activity disrupts the reward pathway and can reduce drug-taking and drug-seeking behavior.