Psychology of Consciousness and Circadian Rhythms

Consciousness

• Consciousness is a person's subjective awareness, including thoughts, perceptions, experiences of the world, and self-awareness.
• Is consciousness an illusion?
• Are there neural correlates of consciousness?
• Are certain brain structures important, or is consciousness an emergent property?
• The "Hard Problem of Consciousness" is the difficulty in explaining subjective experiences.

Sleep: A Predictable Schedule

• Circadian rhythms are biological rhythms with a ~24-hour periodicity.
• Entrainment is the synchronization between biological rhythms and external cues (zeitgebers).

Light Entrainment

• Slowly changing light levels are detected by specialized ganglion cells in the retina.
• Light signals travel to the brain via the optic nerve to the optic chiasm.
• The suprachiasmatic nucleus (SCN) receives light information, situated above the optic chiasm.
• The SCN stimulates melatonin release in the pineal gland.
• Melatonin accumulates with darkness, signaling the onset of sleep.

Staying on Schedule

• Endogenous rhythms are 'free-running' biological rhythms generated by our body independently of zeitgebers.
• Genetic feedback loops control these rhythms.

Why Do We Sleep?

• The restore and repair hypothesis suggests sleep rebuilds energy levels and repairs the body from daily activities (often called "housekeeping").
• The preserve and protect hypothesis states sleep preserves energy and safeguards the organism from harm, especially important for predator-prey distinctions.

Sleep Stages

• Beta waves occur when awake.
• Alpha waves occur during a drowsy state, marked by a loss of attention.
• Stage 1 sleep has decreasing heart rate, blood pressure, and breathing.
• Stage 2 sleep is marked by decreased responsiveness to external stimuli; sporadic brain activity.
• Stages 3 and 4 slow brain activity and present difficulty waking.
• REM sleep is characterized by quickening brain waves, deep relaxation, inhibited body movement, and rapid eye movements (REM).
• REM sleep also involves paradoxical sleep and REM rebound.

Sleep Cycles and REM

• REM sleep happens in cycles throughout the night.
• A typical cycle involves progression through NREM sleep stages to a REM episode.
• In one cycle there are several NREM and REM episodes

Sleep Over the Lifespan

• There's no single magic number for sleep needed; the amount varies with age and genetics.
• Sleep duration has an important developmental impact.

Sleep and Learning

• REM sleep facilitates learning of complex tasks.
• Late REM phases are critical for encoding newly acquired information into long-term memory.
• Slow-wave sleep is crucial for integrating and consolidating autobiographical memories through neural replay.

Sleep Deprivation

• Characteristics of sleep deprivation include falling asleep easily, irritability, attention/vigilance deficits.
• Sleep deprivation can cause normal energy if the person is busy but significant malaise sets in when they rest.
• Reading and studying are difficult after sleep deprivation.
• Microsleeps may occur after 2-3 days of sleep deprivation

The Costs of Sleep Deprivation

• Cognitive and emotional deficits can occur with sleep deprivation.
• Sleep deprivation increases risk of accidents (vehicles and medical errors).

Sleep Displacement

• Sleep displacement occurs when someone can't sleep at the usual time.
• Jet lag and daylight saving time cause displacement.

Sleep Hygiene

• Practicing good sleep hygiene helps train the brain and body to readily fall asleep.
• Specific techniques include maintaining a regular sleep schedule, avoiding naps too close to bedtime, and optimizing the sleep environment.

Dreaming

• The psychoanalytical approach to dreaming, from Sigmund Freud (1900), argues dreams are unconscious expressions of wish fulfillments.
• Manifest content refers to the images and storylines of a dream.
• Latent content describes the symbolic meanings of a dream, often linked to suppressed sexual or aggressive urges.

Modern Theories of Dreaming

• Activation-synthesis hypothesis suggests dreams originate from random bursts of brain activity, primarily from the brainstem.
• Problem-solving theory proposes that dreams continue waking thoughts and concerns, facilitating the processing of problems and their solutions.

Memorability of Dreams

• Waking up and associated stress hormones, norepinephrine, and cortisol are correlated with dream recall.

Disorders of Sleep

• Insomnia is classified as onset (difficulty falling asleep), maintenance (difficulty staying asleep), or terminal (waking up too early).
• It can be primary (internal source) or secondary (a result of other disorders)
• Nightmares are vivid, disturbing dreams occurring during REM sleep.
• Night terrors are intense bouts of panic and arousal, usually during NREM sleep.
• Movement disturbances include restless legs syndrome (discomfort and urge to move legs), REM behavior disorder (acting out dreams), and somnambulism (sleepwalking).
• Sleep apnea is a temporary inability to breathe during sleep due to airway blockage.

Narcolepsy

• Narcolepsy is characterized by extreme daytime sleepiness and sudden sleep attacks lasting seconds to minutes, often directly into REM sleep.

Hypnosis

• Hypnosis is a procedure inducing a heightened state of suggestibility but not a distinct state of consciousness.
• Hypnosis includes ideomotor suggestions (actions to be performed), challenge suggestions (actions not to be performed), and cognitive-perceptual suggestions (prompting memory alteration).

Theories of Hypnosis

• Dissociation theory suggests hypnosis involves a division of consciousness.
• Social-cognitive theory emphasizes beliefs and expectations in influencing hypnosis.

Applications of Hypnosis

• Hypnosis can effectively augment medical treatments, alleviate acute pain, and assist in memory recovery but cannot provide evidence in courts.

Mind-Wandering

• Mind-wandering is an unintentional redirection of attention from a current task to an unrelated train of thought.

The Idle Mind Never Rests

• The default mode network (DMN) is a pattern of brain activity associated with self-reflection and introspection.
• Abnormal DMN activity is linked to some disorders.

Disorders of Consciousness

• A spectrum of wakefulness/awareness exists.
• Consciousness can be assessed using standardized scales, like the Glasgow Coma Scale.
• Brain death is a condition where brain stem functions cease, with no potential for recovery.
• Comas are complete losses of consciousness, often associated with absence of pupillary responses, and complete loss of consciousness
• Persistent vegetative states (PVS) are characterized by minimal or no consciousness, with eyes opening but not tracking movement, and normal sleep-wake cycles.
• Minimally conscious states are marked by behaviours suggesting partial consciousness, beyond simple reflexes.
• Locked-in syndrome is a state characterized by awareness and wakefulness, despite an inability to move or communicate verbally.
• Diminished brain activity corresponds with decreased conscious awareness.

Short-Term Drug Effects

• Drugs can modify neurotransmitter activity through either agonistic (increase neurotransmitter) or antagonistic (decrease neurotransmitter) effects.

Dopamine and Reward

• The nucleus accumbens is a crucial area in the brain's reward circuit.
• It's activated when a person engages in rewarding behaviors.

Long-Term Drug Effects

• Repeated drug use often leads to tolerance.
• Tolerance occurs with changes in how the body and brain function in response to continued use of the same drug
• Down regulation of receptors accounts for some changes in response

Alcohol Withdrawal Timeline

• Symptoms of alcohol withdrawal range from anxiety and insomnia to nausea and agitation.
• Withdrawal can include elevated body temperature, hallucinations, fever, seizures, and agitation.

Top-Down Influences

• Past experiences influence drug responses.
• Drug responses depend on the context, i.e., setting and mood.
• Anticipatory responses (e.g., conditioned tolerance) influence drug effects.

Drug Classes: Stimulants

• Stimulants enhance nervous system activity, often prompting wakefulness, alertness, and heightened energy.
• Stimulants like cocaine, amphetamines, and ecstasy can cause euphoria, but induce a quickly developing tolerance with potential for high dependence.

Commonly Abused Drugs: Physical and Cognitive Deterioration

• Physical deterioration associated with drug use often includes neglected hygiene and consumption of unusual substances.
• Cognitive deterioration associated with drug use might include impaired attention or decision-making.

Drug Classes: Hallucinogens

• Hallucinogens cause perceptual distortions, potentially spanning feelings from euphoria to fear and panic.
• Hallucinogens often increase serotonin activity but block glutamate receptors, leading to tolerance that develops slowly.
• LSD, ketamine, DMT, psilocybin, and salvia divinorum are examples of hallucinogens.

Drug Classes: Opiates

• Opiates (narcotics) reduce pain and induce euphoria.
• Opiates promote endorphin release, leading quickly to potent pain relief.
• Opiates quickly develop tolerance.
• Heroin, fentanyl, oxycodone, oxycontin, codeine, and opium are examples of opiates.

Naloxone: Treating Overdoses

• Endorphins act to reduce pain.
• Naloxone is a drug that blocks endorphin receptors, negating opiate-induced effects.

The Opioid and Fentanyl Crisis

• Other opioids are often laced with fentanyl to produce more potent effects.
• Opioid use and overdoses highlight the need for increased treatment efforts.

Drug Classes: Sedatives

• Sedatives (depressants) depress central nervous system activity, prompting drowsiness, relaxation, and sleep.
• Barbiturates and benzodiazepines are examples of sedatives.
• Sedatives quickly develop tolerance with high risk of dependence

Drug Classes: Alcohol

• Alcohol is one of the most commonly used substances.
• Alcohol promotes euphoria, relaxation, and reduced inhibitions.
• Alcohol initially increases GABA activity but then promotes endorphin and dopamine receptors, leading to tolerance that develops gradually.
• Alcohol use risk moderate to high risk of dependence.

Alcohol Myopia

• Alcohol myopia is a narrower focus on specific cues related to immediate desires while ignoring other cues.
• Alcohol myopia effects are particularly noticeable in youth due to still developing frontal lobes

Drug Classes: Marijuana

• Marijuana is derived from the Cannabis plant.
• Marijuana produces euphoria and relaxation; distorted sensory experience and altered perceptual outcomes may occur.
• THC, in marijuana, mimics brain chemicals, impacting sleep and memory.
• Tolerance to marijuana develops slower than other substances.

This quiz explores key concepts in the psychology of consciousness and circadian rhythms. It addresses definitions, physiological structures, and problems related to consciousness, providing insight into the complexities of mental phenomena and sleep patterns.