Unit 04: States of Consciousness and Sleep

Comprehensive review flashcards covering consciousness levels, circadian rhythms, sleep stages, brain waves, dreaming theories, sleep disorders, and psychoactive substances from Unit 04.

How is consciousness defined in the lecture notes?

A person's awareness of external stimuli, internal physiological sensations, and unique personal thoughts about these experiences.

According to the iceberg model shown in this image, how are the three levels of the mind differentiated?

The Conscious Mind encompasses immediate awareness and controllable thoughts; the Preconscious Mind holds retrievable memories; and the Unconscious Mind consists of deep-seated drives (Freud) or processes operating below consciousness like priming (neuroscience).

What are the three categories of alterations to consciousness and examples of each?

Spontaneous alterations (daydreaming, drowsiness, dreaming); Physiological alterations (hallucinations, food or oxygen starvation, orgasm); and Psychological alterations (sensory deprivation, hypnosis, meditation).

What is the natural length of the human circadian rhythm under normal conditions versus a free-running condition?

Under normal conditions it runs on a $24\text{ hour}$ cycle, but a free-running rhythm extends to $25\text{ hours}$.

What is the neural pathway through which light adjusts the biological clock?

Sunlight reaches the retina, which signals the suprachiasmatic nucleus of the hypothalamus, which then directs the pineal gland to regulate the secretion of melatonin.

What role does the Reticular Activating System (RAS) play in arousal and sleep?

Afferent RAS fibers influence arousal; when lesioned, it produces continuous sleep, and when stimulated, it causes arousal and alertness.

What are the primary sleep research tools and their specific measurement targets?

Electroencephalograph (EEG) measures brain electrical activity; ElectroMyograph (EMG) measures muscle activity and tension; and ElectroOculograph (EOG) measures eye movements.

What brain wave types and sleep stages are displayed in this electroencephalogram (EEG) recording?

Waking Beta ($13\text{--}24\text{ cps}$), Waking Alpha ($8\text{--}12\text{ cps}$), REM sleep, NREM-1 (Theta waves, $4\text{--}7\text{ cps}$), NREM-2 (featuring sleep spindles), and NREM-3 (Delta waves, $< 4\text{ cps}$).

What physical phenomena are typically associated with NREM-1 sleep?

A transition from alpha to theta waves, hypnic jerks, and sleep talking.

What characteristic EEG feature defines NREM-2 sleep and how long does this stage typically last?

It is characterized by sleep spindles (brief bursts of brain activity) and lasts approximately $10\text{--}25\text{ minutes}$.

What events typically occur during NREM-3 slow-wave sleep?

Deep slow-wave delta activity ($< 4\text{ cps}$), physical restoration, sleepwalking (somnambulism), and bedwetting.

Why is REM sleep called 'paradoxical sleep'?

Because brain electrical activity appears active and similar to wakefulness, while muscle tone is completely lost (REM atonia) and breathing and pulse are irregular.

How do the durations of NREM-3 and REM sleep change across the night?

They have an inverse relationship: NREM-3 dominates earlier cycles and decreases, while REM periods start out lasting a few minutes and become progressively longer through the night.

How does the Activation-Synthesis Model (Neural Activation theory) explain dreams?

Dreams occur when the brain weaves random brainstem neural firings during REM sleep into a coherent story.

According to Sigmund Freud, what do the manifest content and latent content of dreams represent?

Manifest content is the remembered storyline of the dream, whereas latent content represents the hidden, unconscious, and potentially unacceptable feelings or wishes.

What are the three evolutionary and biological theories of sleep's purpose?

Conservation Theory (sleep evolved to save energy), Adaptive Non-Responding Theory or 'Caveman Theory' (immobilization during night reduced danger), and Restorative Theory (sleep replenishes energy and bodily resources).

What are the differences among complete, partial, and selective sleep deprivation?

Complete deprivation is total lack of sleep for $24\text{ hours}$ or more (mimics intoxication); partial deprivation is limited sleep over days or weeks (impairs coordination and causes chronic sleep debt); and selective deprivation is restricting specific stages like REM or slow-wave sleep (leading to rebound effects).

According to this diagram of physiological effects, how does sleep deprivation alter appetite regulation in the stomach?

It causes an increase in hunger-arousing ghrelin and a decrease in hunger-suppressing leptin.

What clinical criteria define persistent insomnia?

Difficulty falling or staying asleep, or early rising, occurring at least $3\text{ times a week}$ for $3\text{ months}$ without another underlying cause.

What are the primary symptoms and typical onset age for narcolepsy?

Excessive daytime sleepiness, cataplexy, sudden sleep attacks collapsing directly into REM sleep, sleep paralysis, and disrupted nights, with an onset typically between $10\text{--}30\text{ years old}$.

How do night terrors differ from standard nightmares in terms of sleep stage and presentation?

Night terrors occur in NREM-3 within $2\text{--}3\text{ hours}$ of falling asleep and involve intense autonomic panic without memory of a dream, whereas nightmares occur during REM sleep and are anxiety-arousing dreams.

What is REM Sleep Behavior Disorder?

A condition where individuals physically act out their dreams because they lack the normal muscle paralysis (REM atonia) typical of REM sleep.

How do tolerance and withdrawal differ in substance use?

Tolerance is the diminishing effect of the usual dose requiring larger doses to feel the drug's effect, whereas withdrawal consists of physical discomfort and distress upon discontinuing the substance.

How do stimulant drugs affect neural activity, and what are common adverse effects of cocaine and methamphetamine?

Stimulants excite neural activity and speed up body functions; cocaine leads to cardiovascular stress, paranoia, and depressive crashes, while methamphetamine causes irritability, insomnia, hypertension, and seizures.

How does alcohol classify pharmacologically, and what is Korsakoff's Syndrome?

Alcohol is classified as a depressant (slowing neural activity, body functions, and judgment); Korsakoff's Syndrome is an adverse chronic memory disorder associated with severe alcohol abuse.

What synaptic mechanism of heroin action is illustrated in this diagram?

Heroin binds to opiate receptors, shutting down the release of inhibitory neurotransmitters, which allows dopamine to be released unrestricted into the synaptic cleft.

What are the defining characteristics and adverse consequences of hallucinogens such as LSD and Cannabis?

They distort perceptions and evoke sensory images without sensory input; LSD causes rapid heart rate, unpredictable visual trips, and flashbacks, while marijuana can cause impaired memory and learning, lung damage, and psychological risks.

What is split-brain research and what does contralateral organization mean?

Split-brain research studies patients with a severed corpus callosum to observe hemispheric differences; contralateral organization is the structural principle where the left hemisphere controls the right side of the body and vice versa.