psychology, ch 4

invitation to psychology e/8, chapter 4, consciousness and sleep, pg 110-126

biological rhythm

biological rhythm

a periodic mostly regular fluctuation in a biological system that often has psychological implications
e.g. the clock in our brain oversees hormone levels, urine volume, blood pressure, responsiveness to stimulation

endogenous

describe biological rhythms that are generated from within

circadian rhythm

biological rhythm occuring about every 24 hours
evolved as a response to changes in light, air pressure, and temperature
hundreds of rhythms that affect physiology and performance

suprachiasmatic nucleus (SCN)

located in the hypothalamus in a tiny cluster of cells that governs circadian rhythms
sends messages to body and brain to adapt in response to changes in light transmitted to it from receptors in the back of the eye via neural pathways
thus: master pacemaker

melatonin

secreted by brain’s pineal gland
induces sleep and thought to regulate biological clock from light-dark cycle
levels rise in a darkened room and fall in a lightened room

internal desynchronization

a state where biological rhythms aren’t in phase with each other
e.g. people taking planes across time zones or taking new shifts
sleep/wake patterns adjust, then temperature and hormone cycles over several days

seasonal affective disorder (SAD)

depression during winter seasons, which have shorter periods of daylight
individuals report feeling sadness, lethargy, drowsiness, carbohydrate cravings
appears to be a chronic form of jet lag and abnormalities in melatonin production (super high) or response
treated with light therapy

premenstrual dysphoric disorder (PMDD)

severe depressed mood and anxiety before menstruation to the point of impaired daily function (disappears after end of menstruation)
occurs in 2-6% of women
included in DSM-5

alpha waves

brain emits bursts of these waves of higher altitude and fewer cycles when you lay down to sleep

NREM stage 1

a state of light sleep in which you feel yourself on the edge of consciousness, and your brain waves are small and irregular

NREM stage 2

brain emits sleep spindles
minor noises won’t startle you

sleep spindles

occasional short bursts of rapid, high-peaking waves emitted during stage 3/4 of NREM

NREM stage 3/4

brain emits delta waves
breathing and pulse slow
muscles relax
deep sleep in which you are most likely to sleepwalk
closely associated with memory consolidation
tend to get shorter or disappear as REM periods get longer and closer together

delta waves

slow waves with very high peaks emitted during stage 3/4 of nod

rapid eye movement (REM) sleep

sleep periods with eye movement, loss of muscle tone/restricted physical movement, vivid dreams
lasts a few minutes to an hour, averaging 20 minutes
electrical activity similar to that of alert wakefulness (hence paradoxical sleep)

sleep apnea

a disorder in which breathing stops during sleep, causing gasping and momentary awakeness perhaps hundreds of times with the sufferer being none the wiser
occurs in older men and overweight people
caused by blockage of air passages or brain failing to control respiration
causes high blood pressure and irregular heartbeat

narcolepsy

disorder with sudden, unpredictable launches into sleepiness or REM sleep that last 5 to 30 minutes
develops during teenage years
thought to be caused by reduced amounts of a brain protein from autoimmune issue, viral infection, genetic abnormality

cataplexy

narcolepsy symptom where sufferers experience paralysis of REM sleep without being asleep
brought on by laughing excitedly, telling a joke, orgasming

REM behavior disorder

disorder in which muscle paralysis is incomplete or absent, meaning sleepers act out their dreams
sufferers can hurt themselves or others and are at increased risk for Parkinson’s disease and dementia later in life

Patrick & Gilbert, 1896

3 participants (one being an author) stayed awake for 90 hours
physiological, cognitive/perceptual, motor tests every 6 hours
research methods were crude (candle lit something they were supposed to read from 25 cm)
meta-analyses confirm hallucinations are common and sleep-deprived people don’t function very well

consolidation

synaptic changes associated with recently stored memories becoming durable and stable

lucid dream

dream in which dreamer is aware they’re dreaming

activation-synthesis theory

the theory that dreaming results from cortical synthesis and interpretation of neural signals triggered by activity in the pons (in the lower part of the brain)

synthesizing

what the cortex tries to do with random signals originating from the pons during sleep — integrating them with existing knowledge and memories to produce a coherent interpretation