Neuro - dreams

diurnal vs nocturnal vs crepuscular organisms

• diurnal: organisms are active during the day, when the sun is up; ex. dogs, humans

• nocturnal: organisms are active at night when the sun is down; ex. rats, hamsters

• crepuscular: organisms are active at twilight; ex. rabbits, deer

if light cycle is changed, hamsters will…

alter their wake up (phase shift/phase entertainment)

if the cycle is removed altogether, hamsters will…

run off their own schedule (free running)

what does “zeitgeber” mean

“time giver”; how we know when to wake up, how light sets a pattern

where does the circadian clock live

the hypothalamus

what structure interferes with daily rhythm and what is it’s function

lesions of the superchiasmatic nucleus; maintains daily sleep schedule

what happens if the superchiasmatic nucleus gets damaged

a nonfunctional schedule

what will help attenuate the loss

a zeitgeber

transplant of an SCN from another animal…

can recover rhythm, but will be at the schedule of the donor

waking phase

high frequency with low amplitude (beta waves)

what comes after waking phase

NREM (non rapid eye movement), low brain activity

stages of NREM

• stage 1 - slow frequency activity (alpha waves), not actually asleep yet

• stage 2 - includes sleep spindles and k-complexes, starting to fall asleep

• stage 3 - slow, low frequency waves (slow wave sleep and big lazy waves), actually asleep

REM sleep

similar to wakefulness

one full sleep cycle

• NREM —> REM

• 90-110 minutes in humans

REM sleep becomes more common…

as the night goes on, also gets longer

we often wake up during…

REM; waking up can actually take the place of REM

what do marine mammals do during sleep

they switch between hemispheres; one hemisphere is more active and the other is doing NREM and REM

when do dreams and nightmares occur

during REM sleep

dreams typically activate _____ as wakefulness

the same neurons

nightmares are dreams about

upsetting or discomforting things

night terrors occur during ____ and are often ______

NREM; not remembered explicitly

night terrors have a profound sense of…

fear or crushing, more intense feeling, wake up feeling distressed

how do sleep patterns change with age

• early in life about half of our sleep is spent in REM

• by adulthood, only about 20% is REM

basal forebrain

responsible for slow wave sleep

reticular formation of the brainstem

maintains wakefulnes/alertness

pons

triggers REM sleep

hypothalamus

regulates behavior of the other three regions

what is narcolepsy probably caused by

dysfunction of the hypothalamic sleep center

what causes the hypothalamus to dysfunction

hyperactivity

____ receptors are dysfunctional in narcoleptic dogs

hypocretin

how would loss of hypocretin signaling affect sleep

makes sleep phase transitions disorderly and erratic

sleep may help ____ and ____ memory

contextualize and consolidate

what phase do we consolidate memories best

during slow wave sleep (phase 3 of NREM)