W9 Sleep dreaming and circadian rhythms

Question 1

Recuperatin theories

Answer 1

Sleep is needed to restore homeostasis
Wakefulness cause a deviation from homeostasis

Question 2

Adaptation theories

Answer 2

Sleep is the result of internal timing mechanism
Sleep evolve to protect s from the dangers of the night.

Question 3

Circadian rhythms

Answer 3

are endogenous and persist without environmental cue, however they are modulated by environmental cues (light/external cues), external timing cues: zeitgebers. These adapt the rhythm to the environment.

Question 4

Suprachiasmatic nucleus (SCN)

Answer 4

A major internal clock is the suprachiasmatic nucleus (SCN) of the medial hypothalamus. Lesioning of the suprachiasmatic tract dampens down the circadian rhythm of sleep. Suprachiasmatic nucleus regulates timing of sleep itself.

Question 5

Sleep define behaiorally as:

Answer 5

Reduce motor activity, stereotypic posture (closed eyes), reduce muscle movement, relatively easy reversibility.

Question 6

EGG during the stages of sleep: alert awake

Answer 6

Beta Activity: alert, the EEG high frequency (15-30 Hz), low amplitude electrical activity.

Question 7

EGG during the stages of sleep: restful awake

Answer 7

Alpha Activity: relaxed, the EEG shows medium frequency (8-12 Hz), medium amplitude activity.

Question 8

EGG during the stages of sleep: 1 and 2 stage

Answer 8

Theta activity; 1st and 2nd stage of sleep ( transition sleep-wakefulness): EEG activity of 3.5-7.5 Hz;

Question 9

EGG during the stages of sleep: 3rd and 4th

Answer 9

Delta Activity: 3rd and 4th stages of sleep, high amplitude activity of less than 3.5 Hz; slow-wave sleep. Sleep talking and walking more likely.

Question 10

EGG during the stages of sleep: REM sleep

Answer 10

REM sleep: EEG that is typical of a person who is awake and active (theta, alpha and beta activity).

Question 11

Stage 1

Answer 11

a transition wakefulness-sleep; muscles are still active; the eyes show slow, gentle, rolling movements; some theta activity.

Question 12

Stage 2/3

Answer 12

sleep gets deeper and deeper; the EEG gets progressively lower in frequency and higher in amplitude.

Question 13

Stage 4

Answer 13

the deepest stage of sleep; reached in less than an hour and continues for up to half an hour; relatively high amplitude (delta) EEG activity.

Question 14

REM Sleep

Answer 14

the EEG looks like that of a person who is awake and active although EMG is generally quiet.

Question 15

Baseline cortical state: rats

Answer 15

Baseline cortical state can be altered by electrical BRF stimulation in rats.

Question 16

Little effect of sleep deprivation

Answer 16

logical deduction, critical thinking. Physical strength and motor performance

Question 17

Larger effeect of sleep deprivation

Answer 17

executive function (prefrontal cortex): assimilating hanging information, updating plans and strategies, innovative lateral insightful thinking, reference memory.

Question 18

Sleep deprivation increases sleep efficiency

Answer 18

After sleep deprivation, most of lost stage 4 is regained and SWS is increased. Short sleepers get as much SWS as long sleepers
Naps without SWS do not decrease the night’s sleep. Gradual reductions in sleep time lead to decreases in stages 1 and 2. Little sleepiness produced with repeated REM awakenings, unlike SWS.

Question 19

Default thoery

Answer 19

it is difficult to remain in NREM sleep
Nycamp and others (1998) awoke sleepers in REM for 15 minutes. They were awake for a bit rather than REM Result: no sleepiness or REM rebound the next day
REM-blocking drugs cause periods of wakefulness

Question 20

Brain development and REM

Answer 20

70% REM new born
30% REM 6 months
22% REM adulthood
15% REM late adulthood

Question 21

REM sleep and dreaming

Answer 21

80% of awakenings from REM yield reports of story-like dreams
External stimuli may be incorporated into dreams. Dreams run on real time
Everyone dreams. Sleepwalking and talking are less likely to occur while dreaming. NREM dreams are isolated experiences such as falling

Question 22

Freud’s explanation dreams

Answer 22

are triggered by unacceptable repressed wishes.
Manifest dreams what we experience
Latent dreams the underlying meaning
No evidence for this

Question 23

Activation synthesis

Answer 23

Modern alternative to Freuds explanation of dreams: dreams due to cortex attempt to make sense of random brain activity.

Question 24

depression and sleep

Answer 24

Depression is association with both insomnia and hypersomnia
Total sleep deprivation (TSD) for one whole night improves depressive symptoms in 40–60% of treatments. It is still unknown how sleep deprivation works.
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