Consciousness: Sleep, Dreams, and Psychoactive Drugs

Consciousness

Definition and States

Consciousness refers to our subjective experience of the world, our bodies, and our mental perspectives. It includes both waking consciousness and altered states of consciousness.

• Waking consciousness: Normal awareness of self and environment.

• Altered states of consciousness: Sleep paralysis, locked-in syndrome, out-of-body experiences, near-death experiences, mystical experiences, hypnosis, meditation, and effects of psychoactive drugs.

Sleep and Circadian Rhythms

Circadian Rhythm

Circadian rhythms are biological cycles that occur roughly every 24 hours, regulating sleep, hunger, hormone production, and other bodily functions.

• Regulation: Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus, which acts as the brain's clock mechanism.

• Synchronization: The SCN receives light information from the retina, allowing it to synchronize with the external environment (light-dark cycle).

• Physiological effects: Body temperature, hormone production, and blood pressure follow circadian rhythms.

What is Sleep?

Sleep is a state of low physical activity and reduced awareness, associated with the secretion of several hormones:

• Melatonin

• Follicle stimulating hormone

• Luteinizing hormone

• Growth hormone

Stages of Sleep

Sleep occurs in 90-minute cycles, progressing through five stages:

• Stages 1-4: NREM (Non-Rapid Eye Movement) Sleep

  • No eye movements, fewer dreams.

  • Stage 1: Transition from wakefulness to sleep (10-15 minutes), brain waves slow, brief dream-like images.

  • Stage 2: Further slowing of brain waves, presence of sleep spindles and K-complexes (may help maintain sleep and memory storage), about 65% of total sleep, lasts ~20 minutes.

  • Stages 3 & 4: Deep sleep, characterized by delta waves, crucial for feeling rested, growth hormone production, more time spent in these stages by children, suppressed by alcohol, stage 4 is hardest to awaken from.

• Stage 5: REM (Rapid Eye Movement) Sleep

  • Vivid dreams, rapid eye movements, brain waves similar to wakefulness.

  • Antonia (muscle paralysis), active brain but inactive body.

  • REM rebound: increased REM after deprivation.

Hypnagogic State

The hypnagogic state is the transitional phase between wakefulness and sleep, often accompanied by:

• Hypnagogic imagery (visual, somatic, auditory)

• Myoclonic/hypnic jerk (sudden muscle contractions)

Functions of Sleep

• Adaptive (Preserve & Protect Hypothesis): Sleep restores resources and protects from predatory risks, but increases vulnerability.

• Restorative (Restore & Repair Hypothesis): Sleep restores and replenishes the body, consolidates memory, supports learning and cognitive function, especially during slow-wave sleep.

• Essential for Growth: Necessary for brain development, though the full reasons for sleep are not completely understood.

Sleep Deprivation and Displacement

Sleep Deprivation

• Degeneration of neurons in the brainstem.

• ADHD-like symptoms, increased risk of physical illness, family problems, and substance abuse.

• Impairment similar to a blood alcohol concentration (BAC) of 0.07 (Farlcough & Graham, 1999).

Sleep Displacement

• Occurs when sleep is prevented at the normal time (e.g., jet lag).

• Consuming caffeine before bedtime can delay the internal clock.

Disruptions of Normal Sleep

• Jet lag: Mismatch between internal circadian cycles and environment, causing fatigue and irritability.

• Rotating shift work: Changes in work schedule disrupt circadian rhythm, leading to exhaustion, agitation, sleep problems, depression, and anxiety.

• Bright light therapy can help realign biological clocks.

Effects of Shift Work

• Ages the brain by more than 6 years (Marquie et al., 2014).

• Decline in memory, processing speed, and overall brain power.

• Reversible with about 5 years of regular sleep schedule.

Daylight Savings Time & Car Accidents

• Changes in sleep patterns due to daylight savings time are associated with increased car accidents, especially after the spring shift.

Sleep Deprivation & Mental Health

• Increased stress, emotional overreaction, and impaired emotional regulation (amygdala activation without frontal cortex regulation).

Case Study: Peter Tripp

• Stayed awake for 200 hours, resulting in hallucinations, paranoia, delusions, and personality changes.

Sleep Hygiene for Students

• Maintain a regular sleep-wake schedule.

• Ensure a quiet sleep environment.

• Avoid caffeine after lunch and stimulating activities before bed.

• Use the bed only for sleep, not as an all-purpose area.

Sleep Disorders

Insomnia

• Difficulty falling or staying asleep for at least 3 nights a week for at least 1 month.

• Affects 9-20% of people; higher among students (~25%).

• Associated with ADHD, depression, and employment stress.

• Treatment: Psychotherapy and/or hypnotic medications (e.g., Lunesta, Ambien), but concerns about tolerance and side effects.

Paradoxical Insomnia

• Sleep-state misperception: belief of being sleep deprived despite normal sleep cycles.

• Associated with distress, anxiety, and fatigue; cause is unclear but may involve brain activity during sleep.

Night Terrors & Sleep Apnea

• Night terrors: Sudden waking episodes with screaming, sweating, and confusion, most common in children (ages 3-8), generally harmless.

• Sleep apnea: Blockage of the airway during sleep, can lead to serious health risks (e.g., SIDS).

Narcolepsy

• Rapid and unexpected onset of sleep, directly into REM sleep.

• Associated with cataplexy and lack of orexin (a neurotransmitter).

Other Sleep Disorders

• REM Behaviour Disorder: Lack of muscle paralysis during REM, allowing individuals to act out dreams.

• Somnambulism (Sleepwalking): Walking while fully asleep, occurs during stage 3 sleep, safe to wake the person.

Sleep Paralysis

Features and Cultural Influences

• Occurs when waking up or going into/out of REM sleep.

• Feeling conscious but unable to move, often accompanied by anxiety, terror, and hallucinations (e.g., intruder, chest pressure).

• Cultural interpretations: "Old hag" (Newfoundland), "Kanashibari" (Japan), "Top-hat man" (recent), "Pandafeche" (Italy).

Dreams: Function and Meaning

Freud's Theory

• Dreams as unconscious wish fulfillment.

• Latent content (hidden meaning) vs. manifest content (actual storyline).

• Symbolic interpretation of dream elements.

Evolutionary Theory

• Problem-solving theory: Dreams help process stressful or threatening information relevant to survival.

• Dreams reflect daily concerns and allow for continuous information processing.

• Example: Kurdish children had more intense, threatening dreams than Finnish children.

Neuroscience Theory

• Activation-synthesis theory: Dreams are the brain's attempt to make sense of random neural activity during sleep.

• Dream content reflects emotional and motivational centers (limbic system) with less prefrontal cortex activation.

Psychoactive Drugs

Definition and Effects

Psychoactive drugs are substances that contain chemicals similar to those found naturally in the brain, altering neurotransmission and influencing emotions, perceptions, and behaviors. They can create physiological or psychological dependence.

Stimulants

• Speed up nervous system activity, enhancing wakefulness and alertness.

• Caffeine: Most commonly used, blocks adenosine (which slows brain activity).

• Cocaine: Small doses produce euphoria and energy; large doses can cause anger and paranoia. Blocks dopamine reuptake, flooding the brain.

• Amphetamines: Strong stimulants (e.g., Dexedrine, Benzedrine, methamphetamine) that increase dopamine release, can cause neurological and physical problems, and alter brain structure.

• ADHD Medications: Drugs like Adderall and Vyvanse increase dopamine, serotonin, and norepinephrine; in non-ADHD users, can cause euphoria and increased wakefulness.

• MDMA (Ecstasy): Both a stimulant and hallucinogen; increases serotonin, heightens sensations, and social bonding; chronic use changes brain structure.

Hallucinogens (Psychedelics)

• Produce hallucinations or changes in perception (e.g., LSD, psilocybin, ayahuasca, marijuana, ecstasy, salvia).

• Interest in therapeutic value for mystical experiences and treatment-resistant conditions.

• MDMA & LSD: MDMA increases empathy and connection; LSD produces vivid hallucinations and alters sensory perception and time.

Marijuana (THC: Tetrahydrocannabinol)

• Effects are a mix of excitatory, depressive, and mild hallucinatory.

• Triggers spontaneous ideas, distorted perceptions, and erratic behavior.

• Memory impairment due to cannabinoid receptors in the hippocampus.

• Prolonged use can impair cognitive function (reversible) and reduce dopaminergic function.

• High THC content increases risk of cannabis-induced psychosis (hallucinations, delusions, disorganized thinking).

• Today's cannabis is much stronger than in the past (10x more THC than in the 1970s).

Depressants

• Reduce arousal and stimulation by decreasing neurotransmission and electrical activity.

• Includes alcohol, opioids, benzodiazepines, and barbiturates.

• Used to treat anxiety, panic, and sleep disorders.

Alcohol

• Most commonly used depressant.

• Stimulating at low doses (via dopamine), depressant effects at higher doses.

• Lowers inhibition, impairs judgment, magnifies emotions.

• Females experience stronger effects due to higher BAC at same weight.

Balanced-Placebo Design

• Used to separate physiological effects of alcohol from expectations.

• Placebo drinkers behave similarly to alcohol drinkers, showing the power of expectation.

Your Brain on Alcohol

BAC	Effects
0.01 - 0.05	Behaviour and judgment slightly affected, not intoxicated
0.03 - 0.12	Blurred vision, slurred speech, impaired coordination, reduced inhibitions
0.09 - 0.25	Alcohol poisoning, senses severely impaired
0.25 - 0.35	Coma risk, compromised respiration and circulation
0.45+	Alcohol poisoning may cause death

Depressants: Sedatives

• Barbiturates: Induce sleep or relaxation, psychologically and physically addictive, deadly with alcohol.

• Benzodiazepines: Treat anxiety and panic, highly addictive, excessive use leads to tolerance and memory impairment, deadly with alcohol.

Quaaludes

• Methaqualone (brand name Quaaludes), CNS depressant, increases GABA, sedative and hypnotic.

• Popular in the 1970s, now banned due to widespread recreational use.

Opioids

• Derived from poppy seeds, act on brain's opioid receptors, produce euphoria and pain relief.

• Includes prescription drugs (oxycodone, morphine, fentanyl) and illegal drugs (heroin).

• Highly addictive, can cause respiratory depression and overdose.

• Cycle of addiction: drug is used to avoid withdrawal rather than to feel good.

Summary Table: Sleep Stages and Features

Stage	Brain Waves	Key Features
Stage 1 (NREM)	Alpha/Theta	Transition, light sleep, hypnagogic imagery
Stage 2 (NREM)	Sleep spindles, K-complexes	Further slowing, memory consolidation
Stage 3 (NREM)	Delta	Deep sleep, restorative, growth hormone
Stage 4 (NREM)	Delta	Deepest sleep, hardest to awaken
Stage 5 (REM)	Similar to wakefulness	Vivid dreams, muscle paralysis, REM rebound

Additional info: These notes expand on the original slides by providing definitions, examples, and context for key terms and theories, as well as summarizing the main points in a structured, textbook-style format.