Sleep

Question 1

Where is melatonin released from?

Answer 1

The pineal gland

Question 2

what did michel siffre find out ?

Answer 2

that the circadian rhythm is 25 hours not 24

Question 3

what part of the brain controls sleep?

Answer 3

the superchiasmatic nucleus in the anterior hypothalamus behind the optic chiasm. Has connections to the pineal gland which releases melatonin

Question 4

how do melanopsin receptors work?

Answer 4

light presence sends signals to superchiasmatic nucleus which controls pineal gland and therefore melatonin release.

Question 5

what is phase delay?

Answer 5

when the circadian rhythm is delayed and you wake up later

Question 6

what is phase advance?

Answer 6

when the circadian rhythm is advanced and you wake up earlier.

Question 7

what does the inactivity evolutionary sleep explanation hypothesise?

Answer 7

forces us to remain silent during hours where are more likely to get preyed on. thought to make animals adapt to their environmental niche. however being unconscious is not safe so this theory not proven

Question 8

what does the energy conservation theory hypothesize?

Answer 8

sleep during dark hours when hunting and foraging would be less efficient. Basal temp (10% decrease) and caloric metabolism go down. however if this was true, sleep would not have such a major effect on other aspects of people

Question 9

what is the recuperation/repair theory of sleep?

Answer 9

waste product removal and damage repair. If true then lack of sleep should cause physiological and psychological disturbances, deprivation should be able to get recovered with sleep debt and symptoms should get worse as time goes on.

Question 10

How long did peter tripp and randy gardener stay awake for ?

Answer 10

tripp - 201 hours (8 days). showed psychosis at end
gardener - 264 hours (11 days). showed problems with concentration and STM, moodiness and did not recover debt in the following week

Question 11

what is the glymphatic system?

Answer 11

when changes of vasodilation in the brain pump CSF around the brain. this interacts with interstitial (ec) fluid and picks up the waste products of metabolism to transport away. levels increase when sleep deprived.

Question 12

what to EEG, EOG and EMG measure

Answer 12

EEG - overall electrical brain activity
EOG - eye movement (optic)
EMG - muslce activity (m for muscle)

Question 13

what are the characteristics of the different stages of sleep?

Answer 13

awake - high freq beta waves
drowsy - alpha start
stage 1 and 2 - theta, spindles and mixed EEG activity
stage 3 and 4 - slow wave, more delta (slower)
REM - loss of muscle tone, low-voltage and high-frequency waves similar to being awake. 90% dreaming during REM

Question 14

what does early/SWS sleep effect memory wise?

Answer 14

paired associate word list, declarative/explicit (somatic and episodic)

Question 15

what does late/REM sleep improve memory wise?

Answer 15

mirror drawing, procedural/implicit memory

Question 16

what was improved when presented during SWS compared to REM/conscious?

Answer 16

smell recollection, cueing memories

Question 17

does sleep increase or decrease problem solving and insight?

Answer 17

increase (Wagner et al, Nature) - sequqence word completion task

Question 18

what is hypnagogia?

Answer 18

involuntary spontaneous dream-like experiences that incorporate recent wake experiences. the transition between being awake and asleep

Question 19

what state of mind is non-rem stage 1 sleep associated with?

Answer 19

hypnagogia

Question 20

what are sharp-wave ripple events and when do they occur?

Answer 20

during SWS, a quick recollection of events occurs due to cells that were active in wake experiences being activated faster but still in the same order. this occurs in the hippocampus

Question 21

what are sleep spindles? and the difference between sharp-wave ripple events?

Answer 21

sleep spindles are associated with memory recall and the more dense the spindle is the more consolidated the memory will be. they occur with sharp wave ripples.

Question 21

what are sleep spindles? and the difference between sharp-wave ripple events?

Answer 21

sleep spindles are associated with memory recall

Question 22

how do the SWRs and sleep spindles help memory consolidation?

Answer 22

experience is encoded in the hippocampus and the representation of the experience is replayed at high speed which creates a SWR. the sleep spindles reflect how much the relayed experience engaged with the neocortex

Question 23

what did plihal and born study?

Answer 23

used a paired associate word list plus a mirror drawing task to test what parts of memory sleep affects