PSYC202 Final Sleep

Circadian rhythm

24-hour biological cycle influential on the regulation of sleep & other physical responses

Zeitgeber: time giver

exposure to light readjusts people’s biological clocks

Hypothalamus is…

a circadian clock

Suprachiasmatic nucleus (SCN)

influences by light & controls the release of melatonin in the pineal gland

mammals receive light directly

Sleep stage 1

5-10 minutes; presence of theta waves

Sleep stage 2

turning point in sleep; brief bursts of higher-frequency brain waves

K-complexes

temporal inhibition of neuronal firing so that we don’t wake up after a disturbance

occur after a disruption in the environment (noise)

Sleep spindles

brief spikes generated by the thalamus; handle inhibition of brain activity

Greater number of __ = better performance on learning tasks

sleep spindles

Stages 3 & 4

slow-wave sleep; high amplitude & low-frequency delta waves

reduction of sensory input

Dreams may occur in what stages?

stages 3, 4, and 5

Stage 5 (REM)

high frequency beta waves in some areas

occurs late in the night

Insomnia

chronic problems getting adequate sleep

Causes of insomnia

anxiety & depression

Narcolepsy

irresistible onsets of sleep during normal waking periods

Causes of narcolepsy

lack of hypothalamic cells that produce orexin & Huntington’s disease

Sleep apnea

frequent, reflexive gasping for air that awakens a person

Causes of sleep apnea

obesity, genetics, hormones, old-age deterioration of brain mechanisms that regulate breathing

Night terrors

abrupt awakening from NREM sleep accompanied by intense autonomic arousal & feelings of panic

Nightmares

anxiety-arousing dreams that lead to awakening

Sleep as a local phenomenon

substantial inhibition in one part of the brain and not so much in another

Sleepwalking

motor cortex is awake while the rest of the brain isn’t

REM behavior disorder

people who move around vigorously during REM periods, acting out their dreams

Lucid dreaming

monitoring areas are awake (frontal)

__ inhibits other areas of the brain not meant to be functioning during sleep

GABA

Fatal Familial Insomnia (FFI)

rare inherited disease that occurs when a critical amount of protein PrP is converted into PrPres, which leads to a degeneration of the thalamus

FFI consequences

absence of sleep spindles & k-complexes

reduction of deep sleep, REM occurs during waking cycles

weight loss, hallucinations, seizures, coma, death

EEG patterns during sleep resemble…

those that occur during learning

Sleep spindles increase after…

new learning

Brain adjustments during learning

strengthening new synapses & weakening/removing old synapses

Reactivation process

consolidation of memories during sleep

Steffen Gais, et al. (2006) study

high school students went to sleep either 3 or 10 hours after learning English-German word pairs

the group that went to sleep earlier had a higher retention rate of the word pairs