Consciousness: Sleep, Dreams, and Psychoactive Drugs – Study Notes

Consciousness

Definition and States

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

• Waking consciousness: Awareness of self and environment.

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

Circadian Rhythms

Biological Clock and Regulation

Circadian rhythms are biological cycles that occur over approximately 24 hours, regulating sleep, hunger, and other bodily functions.

• Suprachiasmatic nucleus (SCN): The brain's clock mechanism, located in the hypothalamus.

• SCN synchronizes with external light via retinal projections.

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

Sleep

Definition and Hormonal Changes

Sleep is characterized by low physical activity and reduced awareness. It is associated with the secretion of several hormones:

• Melatonin

• Follicle stimulating hormone

• Luteinizing hormone

• Growth hormone

Stages of Sleep

Sleep occurs in 5 stages, cycling every 90 minutes:

• Stages 1-4: Non-REM (NREM) sleep – no eye movements, fewer dreams.

• Stage 5: REM sleep – vivid dreams, rapid eye movements.

Stage 1: Transition

• Transition from wakefulness to sleep (10–15 minutes).

• Brain waves slow down.

• Dreams resemble photos.

Stage 2: Falling Asleep

• Further slowing of brain waves.

• Sleep spindles and K-complexes appear (may help maintain sleep and memory storage).

• Comprises up to 65% of total sleep; lasts ~20 minutes.

Stages 3 and 4: Deep Sleep

• Delta waves dominate.

• Crucial for feeling rested.

• Growth hormone production increases.

• Children spend more time in these stages than elderly.

• Suppressed by alcohol.

• Stage 4 is hardest to awaken from.

Stage 5: REM Sleep

• Rapid eye movement; brain waves similar to wakefulness.

• Antonia (muscle paralysis).

• REM rebound: increased REM after deprivation.

• Essential for cognitive function.

Hypnagogic State

The hypnagogic state is the transitional phase between wakefulness and sleep, characterized by vivid imagery and sensations.

• Hypnagogic imagery: Visual, somatic, and auditory experiences.

• Myoclonic/hypnic jerk: Sudden muscle contractions.

Why Do We Sleep?

Adaptive and Restorative Functions

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

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

• Essential for growth and brain development.

Sleep Deprivation & Displacement

Effects and Risks

• Sleep deprivation: Degeneration of neurons, ADHD-like symptoms, increased risk of illness and substance abuse.

• Each hour of deprivation increases risk of physical and mental health problems.

• Effects similar to blood alcohol concentration (BAC) of 0.07.

• Sleep displacement: Prevented from sleeping at normal time (e.g., jet lag, caffeine before bed).

Disruptions of Normal Sleep

Jet Lag and Shift Work

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

• Rotating shift work: Alters circadian rhythm, leading to exhaustion, sleep problems, depression, and anxiety.

• Bright light therapy can help realign biological clock.

Impact of Shift Work

• Shift work can age the brain by more than 6 years.

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

• Effects are reversible (~5 years to recover).

Daylight Savings Time & Car Accidents

• Changes in sleep schedule due to daylight savings time are associated with increased car accidents.

Sleep Deprivation & Mental Health

• Increased stress and emotional reactivity.

• Lack of emotional regulation due to amygdala activation (not connecting to frontal cortex).

Case Study: Peter Tripp

• Staged a 200-hour "wakeathon"; experienced hallucinations, paranoia, and personality changes.

• Died at 73 of a stroke.

Sleep Hygiene for Students

• Regular sleep-wake schedule.

• Quiet sleep environment.

• Avoid caffeine after lunch and stimulating activities before bed.

• Use bed only for sleep.

Sleep Disorders

Insomnia

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

• 9–20% prevalence; higher among students (~25%).

• Associated with ADHD, depression, employment stress.

• Treatment: psychotherapy, hypnotics (e.g., Lunesta, Ambien); concerns about tolerance and side effects.

Paradoxical Insomnia

• Sleep-state misperception: belief of sleep deprivation despite normal sleep cycle.

• Distress, anxiety, fatigue; unclear cause but linked to brain arousal during sleep.

Night Terrors & Sleep Apnea

• Night terrors: Sudden waking episodes with screaming, sweating, confusion; most common in children (3–8), usually harmless.

• Sleep apnea: Blockage of airway during sleep; risk of SIDS.

Narcolepsy

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

• Cataplexy (sudden muscle weakness).

• Associated with lack of orexin.

Other Sleep Disorders

• REM behaviour disorder: Not paralyzed during REM, can act out dreams.

• Somnambulism: Sleepwalking during stage 3 sleep; vague consciousness, safe to wake.

Dreams

Function and Meaning

Dreams are a universal aspect of sleep, with various theories explaining their function and meaning.

Freud's Theory

• Unconscious wish fulfillment: Dreams express latent (hidden) desires through manifest content (storyline).

• Symbolic interpretation of dream elements.

• Sexual dreams are only about 10% of all dreams.

Evolutionary Theory

• Problem-solving theory: Dreams help process daily concerns and stressful events.

• Critical survival information is reconsidered and reprocessed.

• Kurdish children have more intense and frequent 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 scenarios reflect dreamer's fears, emotions, and concerns.

• Motivational and emotional centers (limbic system) active during REM; less activation of prefrontal cortex (PFC).

Psychoactive Drugs

Definition and Effects

Psychoactive drugs 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, increasing arousal.

• Cocaine: Small doses increase well-being; large doses cause irritability and violence. Blocks dopamine reabsorption.

• Amphetamines: Strong stimulants (Dexedrine, Benzedrine, methamphetamine); stimulate dopamine release, cause neurological and physical problems, and alter brain structure.

• ADHD medications: Adderall, Vyvanse increase dopamine, serotonin, norepinephrine; improve wakefulness and coping with stress.

• MDMA: Also a hallucinogen; increases serotonin, heightens sensations, increases social bonding, can alter brain structure with chronic use.

Hallucinogens (Psychedelics)

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

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

• MDMA & LSD: Alter serotonin, perception, and neural communication; LSD produces vivid hallucinations and sensory distortions.

Marijuana (THC)

• Effects are excitatory, depressive, and mildly hallucinogenic.

• Triggers spontaneous ideas, distorted perceptions, increased sensitivity to stimuli.

• Memory impairment due to cannabinoid receptors in hippocampus.

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

• High THC content linked to cannabis-induced psychosis (hallucinations, paranoia).

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

Depressants

• Reduce arousal and stimulation; decrease neurotransmission and electrical activity.

• Includes alcohol, opioids, benzodiazepines, 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 (higher BAC).

Balanced-Placebo Design

• Expectations influence social behavior more than physiological effects.

• Placebo drinkers behave similarly to alcohol drinkers.

Your Brain on Alcohol

BAC	Effects
0.01–0.05	Behavior and judgment slightly affected, not intoxicated
0.03–0.12	Blurred vision, slurred speech, impaired coordination
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; CNS depressant, sedative, and hypnotic (increases GABA).

• Popular in 1970s; banned due to recreational abuse.

Opioids

• Derived from poppy seeds; act on brain's opioid receptors.

• Produce euphoria, slow brain activity, depress respiration.

• Highly addictive; prescription drugs (oxycodone, morphine, fentanyl) and illegal drugs.

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

Three Waves of Opioid Overdose Deaths

Wave	Description
1	Prescription opioid overdose
2	Heroin overdose
3	Synthetic opioid overdose (e.g., fentanyl)

Overdose vs. COVID-19 Deaths (2020)

• Opioid overdose deaths have become a major public health concern, sometimes exceeding COVID-19 deaths in certain regions.