PSY1003 SEMESTER 2 - WEEK 9

Question 1

describe behavioural sleep characteristic

Answer 1

reduced motor activity or response to stimulations, stereotypic positions and easily reversible

Question 2

what was Freuds interpretation of dream

Answer 2

triggered by unacceptable, and repressed wishes

Question 3

explain activation-synthesis hypothesis

Answer 3

dreams due to cortex attempting to make sense of random brain activities

Question 4

explain frequency and amplitude of EEG when alert, or relaxed

Answer 4

alert- high frequency (15-30Hz), low amplitude, ‘beta’
relaxed- medium frequency (8-12Hz), medium amplitude, ‘alpha’

Question 5

during first stage of sleep, describe EEGs

Answer 5

transition from wake-sleep, muscles still active, gentle eyes movements
theta
3.5-7.5Hz

Question 6

in stage 2/3, what happens to EEG

Answer 6

progressively get lower in frequency but higher in amplitude

Question 7

in stage 3/4 what happen to EEG

Answer 7

delta, high amplitude, <3.5Hz
slow-wave, sleep walking/talking

Question 8

how long does the sleep cycle last

Answer 8

90min

Question 9

describe carosel animal studies in sleep deprivation

Answer 9

when EEG indicates rat asleep, floor move rat into water
dies after several days (post mortem show extreme stress)

Question 10

what does sleep deprivation have little effects on

Answer 10

logical deduction, critical thinking, physical strength, motor performance

Question 11

what does sleep deprivation have large effect on

Answer 11

EF = assimilating info, updating plan or strategy, innovative lateral insight thinking, reference memory

Question 12

what can 3-4hr of deprivation in one night cause

Answer 12

increased sleepiness, disturbance on mood written tests, poor performance in vigilance test

Question 13

what can 2-3 days of continuous deprivation cause

Answer 13

microsleep (nap of 2-3s)

Question 14

what is impact of sleep deprivation on physiology

Answer 14

reduced temp, increase BP, decreased immune function, hormone change, metabolic change

Question 15

explain why sleep deprivation can increase sleep efficiency

Answer 15

post-dep, most of lost stage4 regained. slow-wave sleep increase
short sleepers get as much slow-wave as long
nap without slow-wave doesn’t impact sleep
little sleepiness if repeatedly woke in REM

Question 16

how do you study REM sleep deprivation, and what 2 consistent effects have shown

Answer 16

wake those in REM, then let them go back to sleep
1. go more rapidly to REM as dep increase, so need to wake them more frequently
2. REM rebound- spend more time in REM post-dep for first 2,3 nights

Question 17

explain impact of sleep on depression

Answer 17

insomnia and hypersomnia
get less slow-wave sleep but no memory disruption
once taking anti-depressants, may not get REM sleep for years

Question 18

how may sleep deprivation improve depression

Answer 18

total sleep deprivation for 1 night improve symptoms for 40-60% but no-one knows why

Question 19

explain link between sleep deprivation and alzheimers

Answer 19

risk factor
sleep used as a waste clearing system- CSF moves through brain and remove waste products (eg; amyloid-B)

Question 20

what is the recuperation theory of sleep

Answer 20

restoring homeostasis, energy levels to clear toxins

Question 21

what is adaptation theory of sleep

Answer 21

internal 24hr timing mechanisms, programmed to sleep at night regardless of what happens during day

Question 22

explain purpose of REM being to process explicit memory, but issues with this

Answer 22

process explicit memory?- inconsistencies, antidepressants REM-blocking don’t impact memory

Question 23

explain default theory for purpose of REM

Answer 23

difficult to remain in non-REM
if wake sleeper in REM, stay awake for 15min
showed no sleepiness/REM rebounds next day suggesting no need for REM sleep if wakefulness sustitues

Question 24

explain why purpose of REM may be brain development

Answer 24

70% REM newborn
30% REM 6 months
continues to decrease in adults

Question 25

what are circadian rhythms

Answer 25

24hrs, endogenous, persist without environmental cues, modulated by external environment which can muddle them “zeitgebers”

Question 26

give example of a zeitegeber

Answer 26

daylight, artificial lights, jet lag

Question 27

define internal desynchronisation

Answer 27

when housed in constant lab environment, sleep-wake and body temp cycles break away from one another

Question 28

what does hypothalamu control

Answer 28

circadian rhythm, body temp, hunger, thirst

Question 29

what is SCN (medial hypothalamus)

Answer 29

has direct projection from retina
major internal clock, dampens circadians, regulate sleep timings

Question 30

what does lesioning SCN result in

Answer 30

disrupt circadian rhythm but not impact time spent asleep, stops circadian periodicity of sleep cycles
transplant SCN into different mammal results in animal adopting different sleep-wake cycle

Question 31

when are SCN neurons active

Answer 31

SCN neuron inactive at night
starts firing at dawn
steady firing pace during day

Question 32

what is pons clocks responsible for

Answer 32

basic rest-activity cycle (BRAC)
cycles of REM sleep, slow wave sleep

Question 33

explain reticular formation

Answer 33

set of interconnected nuclei located throughout brainstem

Question 34

what is pontine reticular formations

Answer 34

brain region without clearly defined border in pon centre

Question 35

what do lesions at midcollicular level of reticular formation cause

Answer 35

damage, but leave sensory fibre intact so produce cortical EEG indicative of continuous slow-wave sleep

Question 36

what cells mediates circadian rhythms

Answer 36

retinal ganglion photoreceptors cells