sleep & dreams

give an example of an area still active during sleep

the auditory cortex

define circadian rhythm

biological clock; regular bodily rhythms that occur on a 24 hour clock

owls vs larks?

owls: most energized in evening with improvements throughout the day

larks: most energized in morning with declines throughout the day

how was REM sleep discovered?

eugene aserinsky (1952): was calibrating an EEG on his sleeping child - monitored throughout the night & correlated with self reports of dreaming upon waking

awake

brain wave: alpha (high freq., amp) & beta (low freq., & amp.)

physiological state: normal activity

cognitive experience: normal activity

duration: ~16 hrs

NREM-1

brain wave: similar to waking alpha & beta waves

physiological state: hypnagogic experienced, sudden movements

cognitive experience: sensory experiences with no sensory input

duration: ~10 mins

NREM-2

brain wave: sleep spindles - bursts of rapid, rthyhmic activity

physiological state: easy to wake

cognitive experience: bedwetting in adolesents

duration: 20 mins

NREM-3

brain wave: slow waves - delta

physiological state: hard to wake

cognitive experience: rich, hallucinatory, story-like emotional dreaming

duration: 30 mins

REM

brain wave: similar to waking/NREM-1 alpha & beta - motor cortex active but blocked at brainstem

physiological state: heart rate rises, breathing rapid/irregular eye movement. genital arousal. otherwise paralyzed

cognitive experience: dreaming

duration: ~10 mins & growing with each cycle

how much nightly REM sleep do we get? how many hours in total over a year?

100 min/night, 600 hrs/year

what are factors that account for the variation in sleep patterns?

genetic variations, culture, socioeconomic factors & macroeconomic factors

what is the role of superchiasmatic nucleus in sleep?

located in hypothalamus, activated by light sensitive proteins in the retina, triggers pineal gland to reduce melatonin

sleep deprivation: biological effects

• increases ghrelin

• decreases leptin

• decreases overall metabolic rate

• increases cortisol

• enhances limbic system’s response to the sight of food

• supresses immune cells

ppl who sleep less than 7 hrs a night are __ more likely to contact a cold

3x

sleep loss is a predictor of?

depression

• 71% higher risk

cyberloafing

wasting time online

insomnia

recurring problems falling asleep & remaining asleep

• affects 1 in 10 adults & 1 in 4 older adults

insomnia treatments

• raising endogenous sleep chemicals through exercise

• restricted caffeine

• avoidance of light prior to bed

narcolepsy

sleep disorder characterized by uncontrollable sleep attacks, lasting directly into REM sleep

narcolepsy treatments

targeted medications

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep & momentary awakenings

sleep apnea treatment

CPAP machine

night terrors

sleep disorder characterized by high arousal & an appearance of being terrified

• targets mostly children

• occurs during NREM-3 sleep

night terrors treatment

resolves as NREM-3 becomes smaller proportion of sleep

dreams

a sequence of images, emotions, & thoughts passing through a sleeping person’s mind

• notable for hallucinatory imagery, discontinuities, and incongruities

REM dreams

vivid, emotional & often bizarre

• 8 in 10 report negative event

freud’s wish fulfillment

dreams preserve sleep & provide a “psychic safety valve” expressing otherwise unacceptable feelings of thoughts

manifest content

the remembered storyline of a dream

latent content

the underlying meaning of a dream

information processing

dreams help sort out the day’s events & consolidate memory

physiological function

regular brain stimulation from REM sleep may help develop & preserve neural pathways

neural activation (activation synthesis)

REM sleep triggers neural activity that evokes random visual memories which are then woven into a narrative

cognitive development

dream content reflects the dreamer’s level of cognitive development

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation