Biopsychology

Question 1

DeCoursey

Answer 1

Endogenous pacemakers
Destroyed the SCN connections in 30 chipmunks who were then returned to natural habitat and observed for 80 days
Sleep/wake cycle disappeared and most were killed by predators

Question 2

Ralph

Answer 2

Mutant hamsters
20hr sleep/wake cycle
SCN tissue from mutants transplanted into normal hamsters + cycle defaulted to 20hrs

Question 3

Suprachiasmatic Nucleus

Answer 3

Bundle of nerves in the hypothalamus
Primary endogenous pacemaker
Nerve fibres connected to eye cross in optic chiasm to left/right visual area of cerebral cortex
Lies above + receives info from optic chiasm
Continues while eyes are closed so biological clock an adjust to changing patterns of daylight

Question 4

Pineal Gland

Answer 4

SCN passes info on day length and light to pineal gland
Increases melatonin production at night (factor of SAD)

Question 5

Exogenous Zietgebers

Answer 5

External factors that reset our biological clocks
Free-running bio clock continues to ‘tick’ in cyclical patterns without zietgebers
Zietgebers bring cycle into line
Interaction of internal + external

Question 6

Campbell + Murphy

Answer 6

Light EZ
Light detected by skin receptor sites even when same info not received by eyes
15 pps woken at various times + light pad shone on back of their knees
Managed to change pps usual sleep/wake cycle by up to 3 hrs for some
EZs don’t need to rely on eyes

Question 7

Social cues (EZ)

Answer 7

Babies
Circadian rhythms begin at 6 weeks
16 weeks rhythms have been entrained by schedules imposed by parents

Question 8

Evaluation of endogenous pacemakers

Answer 8

1) SCN research may obscure other body clocks
Damiola-> changing feeding patterns in mice can alter rhythms of liver cells by up to 12 hrs while leaving SCN unaffected

2) Endogenous pacemakers can’t be studied in isolation
Total isolation studies (like Siffre) are extremely rare
Siffre also used artificial light which may have reset his biological clock every time he turned his lamp on
Lower validity

Question 9

Evaluation of Exogenous Zietgebers

Answer 9

1) Do not have same effect in all environments
Ppl who live in arctic circle spend 6 months in darkness, but have similar sleep/wake cycles all year around (mostly controlled by EPs)

2) Miles-> young man blind from birth, circadian rhythm of 24.9 hrs.
Despite exposure to social cues, sleep/wake cycle counts be adjusted

Question 10

Infradian Rhythms

Answer 10

Frequency of less than 1 cycle in 24 hrs
E.g. menstrual cycle/ SAD

Question 11

Ultradian Rhythms

Answer 11

Frequency of more than 1 cycle in 24 hrs

Question 12

Stern + McClintok

Answer 12

29 women w/ history of irregular periods
Pheromones gathered from 9 at diff stages of cycle (armpit)
Pads worn for 8 hrs to ensure pheromones picked up
Rubbed on upper lip of other pps
68% experienced changes that brought them closer to odour donor

Question 13

Seasonal Affective Disorder
(SAD)

Answer 13

Persistent low mood + low activity levels triggered by winter months when daylight hours decrease
Circannual rhythm
Pineal gland secretes melatonin for longer so knock on effect to production of serotonin

Question 14

Ultradian Rhythms

Answer 14

5 stages of sleep that span 90min + continues throughout the night
1+2- light sleep
1- brain waves high frequency + short amplitude (alpha waves)
2- alpha waves continue w/ random changes in pattern (sleep spindles)
3+4- deep sleep
Delta waves w/ lower frequency + higher amplitude
5- REM sleep
Paralysed, but brain activity resembles awake brain
Theta waves + eyes move around
(Rapid Eye Movement)