Sleep, Dreaming, and Circadian Rhythms (Psych 2113 Exam 3)

Circadian Rhythm

The natural, internal 24-hour cycles that regulate physical, mental, and behavioral changes, most notably the sleep-wake cycle.

Diurnal

Organisms (including most humans) are active during the day and sleep at night

Nocturnal

Organisms that are active at night and sleep during the day

Crepuscular

Organisms are active primarily during the twilights of the day (midday and midnight)

Zeitgeber

Light outside can tell us around the time of day

Suprachiasmatic Nucleus (SCN)

Connects the amount of light received in the retina to the time of day

Pineal Gland

Converts serotonin into melatonin when the retina doesn’t receive much light (night time) & prevents it’s production when the retina processes light (day time)

Polysomonography

How we study the brain while under sleep

Electrooculogram (EOG)

Studies brain activity by measuring and recording eye movement while sleeping

Electromyogram (EMG)

Record electrical activity in skeletal muscles to evaluate muscle tone during sleep stages

Electroencephalogram (ECM)

Uses scalp electrodes to record electric activity in the brain during sleep

Awake (Stages of Sleep)

State of relaxation (Alpha & Beta Waves)

Stage 1 (Stages of Sleep)

Synchronous Activity (Theta Wave Activity)

Stage 2 (Stages of Sleep)

Sleep Spindle (Short bursts of desynchronized activity) & K - Complex (A sharp, high-voltage wave that often occurs moments after sleep spindles)

Stage 3 (Stages of Sleep)

Deepest stage of sleep & low eye/muscle movement (Delta Wave Activity)

REM (Stage 4) (Stages of Sleep)

Dreams Occur / Paralyzed (Theta & Beta Wave Activity)

Ventrolateral (Front Side) Preoptic Nucleus of the Hypothalamus (VLPO)

A cluster of neurons that helps maintain sleep by producing GABA which helps with relaxation)

Raphe Nuclei

A cluster of serotonin producing neurons in the brainstem (midbrain, pons, medulla) that regulate the sleep-wake cycle

Adenosine

A natural neurochemical that regulates energy homeostasis and promotes sleep during wake hours and slows down during sleep. (Caffeine acts as a blocker for this chemical and boost dopamine activity)

Glymphatic System

It clears neurotoxic waste products (proteins/metabolites) and helps distribute compounds like glucose and amino acids

Activation Synthesis Hypothesis

During REM sleep, the brainstem sends random electrical impulses to the limbic system and the cerebral cortex to create dreams using pieces of our memories

Dyssomnias

Sleeping disorders that occur during the process of waking up / falling asleep

Parasomnias

Sleeping disorders that occur during sleep

Insomnia (Dyssomnias)

Struggle falling asleep and staying asleep

Obstructive Sleep Apnea (Dyssomnias)

Causes blockages in the upper airways that restrict oxygen in the body

Central Sleep Apnea (Dyssomnias)

When the brain’s area that controls breathing doesn’t function properly during sleep

Narcolepsy

A disorder that causes difficulty in regulating sleep-wake cycle, resulting in involuntary daytime sleepiness and “sleep attacks”

Sleep Paralysis (Parasomnias)

Causes inability to voluntary muscle movements during sleep

REM Sleep Behavior Disorder (Parasomnias)

Talk or shout, punching and kicking, etc during sleep

Somnambulism (Parasomnias)

Sleep Walking