Paper 2 - Biopsychology - Other Biological Rhythms

Question 1

What is an ultradian rhythm?

Answer 1

A rhythm that occurs more than once in a 24 hour cycle

Question 2

What is an infradian rhythm?

Answer 2

A rhythm that occurs less than once in a 24 hour cycle

Question 3

Give an example of Ultradian rhythms?

Answer 3

BRAC Basic Reset and Activity Cycle (sleep stages)

Question 4

Give an example of infradian rhythms?

Answer 4

SAD(seasonal affective disorder) , menstrual cycle and lack of melatonin during the winter months

Question 5

How frequent is the menstrual cycle?

Answer 5

28-31 days

Question 6

Ovulation occurs when which hormone is at its peak?

Answer 6

LH

Question 7

Once ovulation occurs why does progesterone increase?

Answer 7

To thicken the uterine lining

Question 8

What gland regulates the menstrual cycle called?

Answer 8

Pituitary gland (starting the cycle with FSH)

Question 9

What did McClintock want to study?

What is an answer to her question?

Answer 9

What factors effect the menstrual cycle?

Appart from hormonal contraception, stress and diet

Question 10

From an evolutionary viewpoint why may women’s periods tend to change?

Answer 10

So that they can have babies together as women tend to “tend and befriend”

Question 11

What was the method of McClintocks study?

Answer 11

Procedure: 29 women with a history of irregular periods. Samples of pheromones were gathered from nine of the women at different stages of their menstrual cycles, via a cotton pad placed in their armpit. The pads were worn for at least eight hours to ensure that pheromones were picked up.
The pads were treated with alcohol and frozen, to be rubbed on the upper lip of the other participants. On day one, pads from the start of the cycle were applied to 20 women, on day two, they were all given a pad from the second day of the cycle and so on.

Question 12

What was the results of McClintock’s study?

Answer 12

Results: the study found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’.

Question 13

From a natural selection viewpoint why may women’s periods tend to change?

Answer 13

Women can help each other look after the children and more children are going to survive and pass on their genes (tend and befriend)

Question 14

What are some confounding variables to McClintock’s work?

Answer 14

Diet, exercise, health, previous menstucal cycle history

Question 15

Why is the fact that a lot of research is done on animals a weakness of study’s?

Answer 15

Animals have a “season” also called heat which doesn’t happen as frequently as a human menstrual cycle

Question 16

What is SAD?

Answer 16

SAD: is a depressive disorder which has a seasonal pattern of onset (DSM-5)
The main symptom are persistent low mood alongside a general lack of activity and interest in life

Question 17

Why may circadian rhythms be affected in the winter?

Answer 17

Annual rhythms are related to seasons, in particular migration in response to lower body temperatures

This also may affecthuman behavior, as research suggests seasonal variations in mood in particular for women, with some people becoming severely depressed in Winter months.

Question 18

What is circannual rhythm?

Answer 18

Circannual rhythm happens every year
Circannual rhythm: melatonin is secreted for a longer period of time due to the lack of light.

Question 19

Why are circannual rhythms associated with SAD?

Answer 19

Circannual rhythym: melatonin is secreted for a longer period of time due to the lack of light. This is thought to have an effect on the neurotransmitter serotonin, creating depressive symptoms

Question 20

When dlo most people die?
When are there the most heart attacks?
Why?

Answer 20

Most people die in January
Most heart attacks happen in the winter

This could be due to SAD as well as Christmas being very stressful (a generally stressful season)?

Question 21

What was Eastman’s study?

Answer 21

He randomly assigned 96 patients with winter SAD to one of 3 bright light treatments that were about 10-20X brighter than ordinary indoor lights

Patients either got 1.5 hours of sitting in front of the light in the morning or in the evening, or a morning placebo of 2 deactivated negative-ion generators

Question 22

What were the results of Eastmans study?

Answer 22

After 3 weeks
Significantly more people in the morning group had showed significant or near complete removal of their symptoms
The evening group showed improvement (just not significant improvement) over the placebo group

But 30% of the placebo group also seemed to recover

Question 23

What was the conclusion of Eastmans study?

Answer 23

Effective phototherapy could lead to full remission of depression

Question 24

What is phototherapy?

Why is it done?

Answer 24

When participants sit in front of a bright light

To try and increase the light getting to our body which should then start to produce serotonin (when there is a lack of sunlight in the winter months)

Question 25

What are the different stages of sleep?

Answer 25

Stage 1,2,3,4 and REM sleep

Question 26

What is the function of stage 1 sleep?

Answer 26

Non REM sleep - transition from wakefulness it lasts less that 10 mins and is marked by slowing heartrate, breathing and eye movement as well as relaxing of muscles

Question 27

What is the function of stage 2 sleep?

Answer 27

Non REM sleep id the period of light sleep before you enter deeper sleep.

It lasts roughly 20 mins.

Furthermore slowing of heart rate, breathing and the brain begins to procede bursts of rapid, rhythmic brain waves actively known as sleep spindles

Question 28

What is the function of stage 3,4 sleep?

Answer 28

Final stage of non REM sleep
It is the deepest period of sleep and lasts 20-40 mins. Your heart rate and breathing rate are at their lowest and your muscles are so relaxed that is may be hard to awake you

Question 29

What is the function of REM sleep?

Answer 29

Occurs 90 mins after sleep onset and is much deeper sleep that any of the 3 stages on non REM sleep
Defined as rapid eye movement and an almost complete paralysis of the body

Question 30

What is entrainment?

Answer 30

the process of resetting our biological clocks in line with external times cues

Question 31

What can entrainment help with?

Answer 31

This can help synchronise the circadian rhythms

Question 32

What is the suprachiasmatic nucleus (SCN)?

Answer 32

The SCN is a tiny bundle of nerve cells located in the hypothalamus in each hemisphere in the brain. This is one of the endogenous pacemakers in mammalian species and is influential in maintaining circadian rhythms

Question 33

What is the optic chasm?

Answer 33

Nerve fibres connected to the eye cross in an area called optic chiasm on their way to the visual area of the cerebral cortex

Question 34

What is counterintuitive about the optic chasm?

Answer 34

It can receive info about light even when our eyes are closed

Question 35

What does the Pineal gland do?

Answer 35

Secretes melatonin at the night and inhibits it during the day

Question 36

What did DeCoursey do in his study?

Answer 36

DeCoursey et al. (2000) destroyed the SCN connections in the brains of 30 chipmunks, who were then returned to their natural habitat an observed over 80 days.

Question 37

What were the conclusions of DeCoursey’s study?

Answer 37

The sleep/wake cycle of the chipmunks disappeared and by the end of the study, a significant proportion of them had been killed by predators (due to them being awake and vulnerable, when they should have been asleep).

Question 38

What did Ralph (1990) do?

Answer 38

Ralph et al. (1990) bred ‘mutant’ hamsters with a 20- hour sleep/wake cycle. When the SCN cells from the foetal tissue of mutant hamsters were transplanted into the brains of normal hamsters, the cycles of the second group defaulted to 20 hours.

Question 39

Who did a study about avoiding jet lag?

Answer 39

Burgess et al (2003)

Question 40

What was the method of Burgess’s study?

Answer 40

Burgess et al (2003) found that exposure to bright light prior to an east west flight, reduces the time needed to readjust to local time on arrival ps exposed to continuous bright light shifted their circadian rhythm by 2.1 hours whereas those exposed to intermittent bright light shifted their rhythm by 1.5 hours and those exposed to dim light shifted theirs by just 0.6 hours .

Question 41

What were the results of Burgess’s study?

Answer 41

As a result ps in the 1st condition felt sleepier 2 hours earlier in the evening and woke 2 hours earlier in the morning (they had better adjusted to local time)

Question 42

What did Campbell and Murphy’s study try to show?

Answer 42

This study demonstrated that light may be detected by skin receptor sites on the body even when the same information is not received by the eyes.

Question 43

What was the method used in Campbell and Murphy’s study?

Answer 43

Procedure: 15 participants were woken at various times and a light pad was shone on the back of their knees

Question 44

What were the results of Campbell and Murphy’s study?

Answer 44

Results: the researchers managed to produce a deviation in the participants’ usual sleep/wake cycle of up to 3 hours.

Question 45

What did Campbell and Murphy’s study suggest?

Answer 45

This suggests that light is a powerful exogenous zeitgeber that need not necessarily rely on the eyes to exert its influence on the brain.

Question 46

How do social cues help people (what type of people?) develop their circadian rhythms?

Answer 46

At about 6 weeks of age, the circadian rhythm begins and by 16 weeks, most babies are entrained.
The schedule imposed by parents is said to have a large influence here including adult-determined mealtimes and bedtimes.

Question 47

How can social cues help reduce jet lag?

Answer 47

Jet lag- Research has suggested that adapting to local eating and sleeping times is an effective way of entraining circadian rhythms.
(Like hoe the babies develop their circadian rhythms)

Question 48

What is the positive evaluation of McClintock’s study?
Include the counterargument

Answer 48

McClintock’s study has evolutionary value. It may have been evolutionarily advantages for females to menstruate together and therefore all fall pregnant at the same times so babies could all be cared for at the same time to increase the chance of the offspring survival
However:
Schank argued that if there were too many females cycling together it may create too much competition for healthy and fit sperm and concluded that the avoidance of sychroncy would appear to be the most adaptive evolutionary cycle

Question 49

What is the evidence to suggest the idea of distinct stages in sleep?

Answer 49

Dement and Kleitman (1957) - they measured brain activity (with EEG) (with ppts without caffeine and alcohol in their blood)
They found that REM sleep was highly correlated with more vivid and active dreaming.
They also found that when you are woken up in REM sleep you remember the most about dreams
• Replications of this investigation have noted similar findings, though the small size of the original sample has been criticised.

Question 50

What is the positive evaluations of the use of animal studies in research into circadian rhythms?

Answer 50

• The role of pheromones in animal sexual selection is well documented.
• Sea urchins release pheromones into the surrounding water so other urchins in the colony will eject their sex cells simultaneously.
• In contrast evidence for the effects of human behaviour remains speculative and inconclusive

(But since other animals do it it increase the chance that we do)

Question 51

What are the practical applications of SAD?

Answer 51

One of the most effective treatments for SAD is phototherapy.
• This is a light box that simulates very strong light in the morning and
evening.
• It is thought to reset melatonin levels in people who have SAD (Eastman et al., 1998)
• However, the placebo effect calls into question the effect of phototherapy

Question 52

Explain the evaluation methodological limitations in synchronisation studies (McClintock)

Answer 52

Stress, lifestyle, diet and exercise can all effect a women’s cycle so these may act as confounding variables suggesting that the results of McClintock’s study could be down to chance

A study done by Trevathan (1993) failed to find any evidence of menstrual synchrony
29 cohabiting same sex couples kept a diary of their intimacy and their cycles

Question 53

What do you need to know about the menstrual cycle?

Answer 53

FSH
O
LH
P
Each process is a infradian process which causes the other

Question 54

Have a general idea about what the different sleep graphs look like?

Answer 54

Question 55

What is a general evaluation of sleep research?

Answer 55

It is very scientific using EEGS etc

Question 56

What is a general issue with studies about how EP’s and EZ’s influence the sleep wake cycle?

Answer 56

Ethics (Hamster study may have disrupted the ecosystem)
Generalisability

Question 57

State the evidence that EZs can effect the sleep wake cycle

Answer 57

Siffre: (light is an EZ)
Campbell and Murphy (1998) shone light onto the back of the knees of 15 participants when they woke them at various points in the night. They managed to vary their sleep cycle by up to three hours.
This shows that light can effect the sleep wake cycle

Question 58

Explain the negative evaluation of EP and EZ in circadian rhythms: Faulty Assumptions

Answer 58

Research has revealed there are numerous circadian rhythms in many organs and cells of the body.
• Although they are influenced by SCN, they can act independently.
• Damiola et al. (2000) demonstrated how changing feeding patterns of mice could alter the circadian rhythms of cells in the liver by up to 12 hours, whilst leaving the rhythm of the SCN unaffected.

Question 59

What are some examples of other independent circadian rhythms?

Answer 59

Peripheral oscillators found in the adrenal gland, oesophagus, lungs, liver, pancreas, spleen. Thymus and skin.

Question 60

What is a peripheral oscillator?

Answer 60

A circadian oscillator which is located in cells tissues or organs outside of the SCN

Question 61

What is an extremely important study?
Why?

Answer 61

Campbell and Murphy
It could be used as a negative evaluation of all other studies for potentially having a confounding variable

Question 62

Explain the evaluation about the EZs total role

Answer 62

They may be overrated in reference to the sleep wake cycle:

Blind from birth (a young man) with a circadian rhythm of 24.9 hrs. Despite exposure to social cues, his sleep wake cycle could not be adjusted , and consequently, he had to take sedatives at night and stimulants in the morning to keep pace with the 24 hour world.
The difference is likely due to the lack of SCNs in the eyes due to natural blindness.
Since 24.9. Is close to 24 hours it suggests that light isn’t so important.
Furthermore, people in Alaska still function without light for a month at a time

Question 63

Explain the limitation of generalisation in terms of EP’s?

Answer 63

Animals who are nocternal produce melatonin to wake up. These shows a difference in our sleep/wake cycle. Generalisability is not possible in this studies.

Question 64

Explain the negative evaluation of EZ and EP in the sleep wake cycle: Methodological Issues

Answer 64

Campbell and Murphy’s study has yet to be replicated and researchers have been critical of methodology, suggesting confounding variables.
Furthermore other confounding variables may include other EZ such as social cues (hunger)