Ch 7 S1-2

consciousness

subjective awareness of ourselves and our environment

biological rhythms

periodic physiological changes

annual cycles

e.g. geese migrate, bears hibernate, humans may suffer seasonal affective disorder (SAD)- depressed mood; much more common in winter or northern latitudes; 4x more common among women

28 day cycles

female menstrual cycle

24 hour cycles

circadian rhythm (lit. about a day)- biological clock, varying alertness, body temp., hormone secretion, etc.

ninety minute cycles

sleep cycles ideal nap

SAD

seasonal affective disorder - depressed mood; much more common in winter or northern latitudes; 4x more common among women

varying degrees of control

may be affected spontaneously: daydreaming, drowsiness, dreaming

physiologically induced

hallucinations, orgasm, food or oxygen starvation, drugs, sleep deprivation, etc.

psychologically induced

sensory deprivation, hypnosis, meditation, psychosis, etc.

automatic tasks

many tasks can become automatic, but novel tasks require conscious attention

Circadian rhythm

Controlled by the suprachiasmatic nucleus, responsive to light-sensitive proteins in the eyes, regulating the pineal gland that secretes melatonin.

Melatonin

A sleep-inducing hormone regulated by the pineal gland.

Adenosine

Accumulation of this substance inhibits certain neurons, making us sleepy.

Sleep

Natural, reversible loss of consciousness.

Sleep Stages

90-minute cycles of sleep including REM and NREM stages.

REM sleep

Rapid eye movement sleep when dreams commonly occur; also known as paradoxical sleep.

Sleep paralysis

Occurs upon waking when the brainstem is still blocking motor cortex signals.

NREM sleep

Non-REM sleep stages, including three stages with the deepest occurring earlier in the evening.

Alpha waves

Slow brain waves characteristic of a relaxed, awake state.

Hallucinations

Sensory experiences without stimuli that may occur in NREM-1.

Hypnogogic sensations

Feelings of falling or weightlessness at the moment of sleep.

Sleep spindles

Bursts of brain activity occurring in NREM-2.

Delta waves

Large, slow brain waves associated with deep sleep (NREM-3).

Bedwetting and sleepwalking

May occur during deep sleep (NREM-3).

Selective attention

Certain stimuli may still awaken a sleeper, such as a baby's cry.

REM duration

Cyclically happens before stage 1, increasing through the night, accounting for 20-25% of total sleep.

Genital arousal

Occurs even with non-sexual dreams; ½ the night for younger men, ¼ for older men.

Sleep deprivation effects

Affects memory, concentration, mood, immune system, and increases accidents.

Teen sleep needs

Teens need 8-9 hours of sleep but average only 7 hours.

Chronic sleep debt

Alters metabolic and hormonal functioning, contributing to obesity, hypertension, and memory impairment.

Sleep theories

Various explanations for why we sleep, influenced by individual and cultural factors.

sleep protects

not out at night (evolutionary); we are not nocturnal animals

restore and repair

body recovery, neuron repair when we grow in adolescence

remembering

review of experiences; may boost creativity and insight

growth

pituitary gland releases growth hormone; improves physical performance

insomnia

recurring problems in falling or staying asleep (10-15% of adults); sleep is disrupted

narcolepsy

uncontrollable lapses (c. 5 mins) into sleep (rare: 1 in 2000); often in response to strong emotions

sleep apnea

temporary cessations of breathing and momentary awakenings (1 in 20); especially overweight; heart attack and stroke risk

night terrors

high arousal, terrified disposition; mostly children; during NREM-3 sleep; not dreaming; seldom remembered screaming in bed

sleepwalking

also occurs during NREM-3; sleeptalking can occur at any stage of sleep; both are also more common among children

dreams

recent or significant experiences and interests often get incorporated into our dreams

Why Do We Dream?

to satisfy our own wishes

manifest content

the storyline of a dream

latent content

underlying meaning of a dream

to file away memories

sift, sort day's experiences

to develop and preserve neural pathways

provide periodic stimulation to preserve neural pathways

activation-synthesis theory

our brains try to make sense of random neural activity

REM rebound

increased REM sleep if deprived