Lecture 13

Question 1

circannual cycle

Answer 1

Yearly

• hibernation, fat metabolism

Question 2

infradian

Answer 2

longer than a day - shorter than a year

• menstrual cycle

Question 3

circadian

Answer 3

daily

• sleep-wake cycle

Question 4

ultradian

Answer 4

shorter than a day

• eating

Question 5

endogenous rhythsm

Answer 5

are driven internally from within the body (biological clock)

Question 6

exogenous rhythms

Answer 6

are driven externally

e.g., by the sun or the seasons

Question 7

zeigerbers

Answer 7

environmental events

• periodical synchronisation to environmental events that provide a clock setting cue keeps our biological clock on the 24h cycle
• only able to entrain the circadian rhythm if they occur at the same time each day

Question 8

what is the most important biological clock structure

Answer 8

suprachiasmatic nucleus

Question 9

suprachiasmatic nucleus

Answer 9

• part of the hypothal
• located just above the optic chiasm
• receives input from photosensitive retinal ganglion cells via the retinohypothalamic tract
• core neurons are not rhythmic; they entrain shell neurons which are genetically programmed for rhythmicity

Question 10

nonphotic events

Answer 10

are signaled to the SCN by the intergeniculate leaflet (lateral thalamus) and Raphe nuclei

Question 11

pace maker - SCN

Answer 11

SCN acts as a biological master clock

• it contains pacemaker cells that have an endogenous rhythm

Question 12

pacemaker - slave oscillators

Answer 12

these pacemaker cells entrain slave oscillators; other brain structures with circadian rhythmic activity

Question 13

circadian rhythmic activity at night

Answer 13

pineal gland > melatonin

• melatonin activates the parasympathetic rest-and-digest system

Question 14

circadian rhythmic activity during the day

Answer 14

pituitary gland > adrenal glands > cortisol

• cortisol supports arousal activities in the sympathetic system

Question 15

sleep recording techniques (3)

Answer 15

1. brain activity (EEG)
2. muscle activity (EMG)
3. eye movement (EOG)

Question 16

hypnogram

Answer 16

• first ahlve of the typical night is mainly characterised by NREM sleep, second half REM sleep
• NREM-REM = 90 mins, 5 times a night

Question 17

REM rebound

Answer 17

if you do not sleep long enough one night, the REM sleep occurs at the beginning of the the following night

Question 18

activation synthesis theory

Answer 18

dreams are an epiphenomenon of random brain activity

Question 19

coping theory

Answer 19

dreams are biologically adaptive and lead to enhanced coping strategies for threatening life events

Question 20

continuation theory

Answer 20

we are problem solvers while awake, and this continues during sleep

Question 21

the basic rest-activity cycle (BRAC)

Answer 21

activity and rest are organised in time blocks of 90 mins

• rem sleep also occurs (evidence for continuation theory)

Question 22

sleep as a biological adaption process

Answer 22

• animals sleep to save energy
• diurnal animals sleep to avoid bumping into objects at night
• predators typically sleep more than prey animals

Question 23

sleep as a restorative process

Answer 23

body recovery: growth hormone during sleep
brain recovery: resting state and cleaning up

Question 24

sleep and explicit memory storage

Answer 24

in animals: explicit memory traces in the hippocampus are consolidated during NREM sleep
in humans: consolidation of implicit memory occurs during REM sleep

Question 25

reticular activating system (RAS)

Answer 25

• main brain area responsible for sleeping-waking behaviour
• in brainstem
• stimulation of RAS stimulates the (hypo)thal and cortex and produces an awake EEG patter
• inhibition produces a sleep EEG patter

Question 26

damage to RAS

Answer 26

results in coma

Question 27

ventrolateral preoptic nucleus (VLPO)

Answer 27

in the hypothal contains a sleep-wake switch
- brainstem contains a NREM-REM switch

• the switch of off when awake, RAS is active
• switch is on during sleep, inhibits the RAS

Question 28

NREM sleep disorders

Answer 28

insomnia
hypersomnia - difficulty waking up or staying awake due to prolonged NREM sleep

Question 29

REM sleep disorders

Answer 29

narcolepsy
sleep paralysis
cataplexy - sudden loss of muscle tone triggered by arousal