Biopsychology Flashcards

Question

Biological Rhythms - Circadian - Other research

Answer 1

- Aschoff and Wever conducted a study with 11 ppts who lived in a ww2 bunker for 4 weeks and were deprived on natural light - all but 1 participant displayed a circadian rhythm of 24 - 25 hrs - both siffres and this case study suggest that the internal body clock may be slightly longer than 24 hrs and that exogenous zeitgebers just entertain this which are associated with our 24 hr day - however we cannot overestimate affect of exogenous zeitgeber on internal biological clock - folkard - did a study with 15 people who agreed to live in a dark cave for 3 weeks and they went to sleep at 11:45 and woke up at 7:45 on the clock - researchers sped up the clock so that it went from a 24 hr day to a 22 hr day - only 1 ppt was able to adjust to this new schedule - suggests a strong internal biological clock and that it cannot be overrun by exogenous zeitgebers.

Answer 2

1. medical treatments - influences effectiveness of use of drug treatments - this is because circadian rhythms co ordinate to the body's basic processes - there is something known as chronotheraputics - when we can increase effectiveness by adminstering medical treatments to saligh with biological rhythms - for example asprin for heart attacks is more effective at night as people are prone to them more in the mornings 2. individual differences - generalisations are hard to make - the studies used a small sample of ppts - and everyone's sleep/wake cycle varies amongst different people - research even suggests that its around 16-65 hrs it can range from - some people have a naturl preference to go to bed and might be an early bird or late owl so it is really up to the person 3. shifting the school day - researchers suggest we should shift the school day to start later to match with a typical teenagers chronotype aka their sleepwave pattern - this is because they go through hormonal changes so it is difficult for them to fall asleep and adolescent students are found to be sleepy at the start of the day - it is also shown to have a positive affect on academic and behavioral performances and students are less reliant on caffeine. - however, other research suggests that this is disruptive to teachers and students lives as it can mean there is no time for after school activities for example - critics also propose that it will not decrease sleep deprivation as teenagers will just stay up longer - also it is not practical, despite its benefits as younger students will struggle to get dropped off to school with working parents.

Answer 3

- it is an example of infradian rhythms and it is governed by the changes in hormonal levels which regulates ovulation - the cycle is known as the time between the womans first day of her period and the day before her next one - typical period lasts for 28 days - during the cycle: - rising levels of the hormone oestrogen which causes the ovary to develop an egg and release it - known as ovulation - also increasing levels of progesterone which helps thicken the womb lining and prepares the womb/body for pregnancy - however, if pregnancy does not occur, then the egg is absorbed by the body and the womb lining comes away and leaves the body known as the menstrual flow

Answer 4

- the menstural cycle is an endogenous system, however it can be influenced by exogenous factors - there was a study done with 29 women who had a history of irregular periods - samples of the pheremones of 9 women were taken at different stages of their menstural cycle via a cotton pad placed in their armpit - this was left for 8 hours so that the pheremones were properly picked up and absorbed - they were then treated with alchohol and frozen and rubbed on the upper lips of OTHER ppts - each pad was a diff day of the cycle - it was found that 68% of women had changes in their cycle to more closely match with their odour donor.

Answer 5

1. evolutionary basis - menstural synchrony research can be explained by natural selection - adaptive strategy - for our ancestors it may have been adavnatgeous for women to actually have synchronised cycles and be pregnant at the same time - this is because for children who lost their mother during or after childbirth, they still had access to breast milk etc and so it increased their chances of survival 2. methodological issues - other factors can influence the change in cycles such as diet, exercise, stress etc - these are confounding variables and therefore it may be suggested that the synchrony may have been due to chance - other research such as trevathan et al could not replicate findings - so menstural synchrony studies are flawed 3. real - world application - we know that light therapy is an effective treatment for SAD - this is because it uses a box to stimulate extreme light to reset the bodys internal biological clock - helps reduce the affects of SAD in 80% of people - people prefer it over antidepressants as it is regarded as more safe.

Answer 6

- depressive disorder caused by seasonal patterns of onset - general symptoms are persistent low moods, lack of interest in activities and life - also known as the winter blues because the symptoms are triggered during winter months as the daylight hours are much shorter - is an example of an infradian rhythm as it has a yearly cycle (circannual rhythm) - however can also be classified as circadian as it is may be affected by changes in the sleep/wake cycle - psychologists have hypothesised that the hormone melatonin has implications in ocd - this is because during the night the pineal gland secretes this hormone until dawn when there is an increase in light - but during the winter months, there is a lack of light in the morning so this process continues for much longer - this has a knock-on effect on the production of hormone serotonin in the brain which has implications in the onset of depression

Answer 7

- sleep cycle is categorised by 5 distinct stages of sleep - each stage has a duration of around 90 minutes - each stage has different brain wave patterns and this can be monitored on an eeg - stage 1: - light sleep, easy to wake up, alpha waves so the frequency is high and amplitude is low - stage 2: - alpha waves continue throughout with occasional changes in pattern known as sleep spindles - stage 3/4: - deep sleep, difficult to wake up, slow wave sleep (sws), has delta waves so there is low freq and high amp - stage 5: - REM sleep stage, body is paralysed but brain activity resembles the awake brain, has theta waves which causes eye to occasionally move known as rapid eye movement and dreams usually occur in this stage but can also occur during stage 3/4.

Answer 8

1. improved understanding : - helped improve our understanding of age related changes in sleep patterns - practical value - sleep scientists have suggested that sws is reduced in old people and the main hormone produced during sws is also reduced in old people - so sleep deficits may be the cause of various issues in older people like reduced alertness but relaxation and meditation can help increase and improve sws 2. individual differences - significant variations between people - hard to describe normal sleep - study has been done which shows the differences in the duration of sleep stages in people e.g 3&4 - this suggests it may be biologically determined 3. sleep lab - conducting this in a lab is good as we can eliminate extraneous variables like room temp which may affect sleep - however people have to be hooked up to complex machine to do this so it does not mirror actual sleep pattern and way people sleep - inaccurate and people should sleep in own homes and this should be compared with results

Answer 9

- main ep is the scn - it is the primary ep in all mammalian species - it is influential in maintaining circadian rhythms - nerve fibres connected to eye cross of optic chiasm and the scn is located directly above this - it receives info directly from its structure about light and this continues while our eyes are closed - this enables the biological clock to adjust to changing patterns of light while we are asleep

Answer 10

- there was a study done where the scn of 30 chipmunks was removed from their brains and they were sent back into their natural habitat and observed for 80 days - it was found that their sleep wake cycle diasppeared and a significant proportion of them were targeted ad killed by predators - this is because they were awake and vulnerable to attack when they should have been asleep - another study was done by a researcher who bred mutant hamsters to have a 20 hour wake cycle - cells from their scn were taken from their foetull tissue of their brain and then taken and transplanted into brains of normal hamsters - the normal ones automatically had a 20 hr cycle

Answer 11

- scn passes info about day lengths and light to the pineal gland and this secretes the hormone melatonin - this process occurs during the night and induces sleep and is inhibited during periods of wakefulness.

Answer 12

1. interactionist system - it it very rare and difficult to find studies of endogenous pacemakers which were isolated - total isolation studies again are rare and studies like siffre's still used artificial light such as a lamp and this could have reset his biological clock - endogenous and exogenous interact with each other in everyday life - it makes little sense to separate them 2. ethics - animal studies have been justified because there are similar mechanisms across species - there is evidence of the scn and pineal gland in the brains of chipmunks and hamsters so generalizations to humans can be made as mammalian brain structure is similar to this - but ethics means that many of the animals had been exposed to risk and were harmed or some even killed - researchers should investigate effects of ep without endangering animals

Answer 13

- these are external factors of the environment which can reset our biological clock through entrainment - interaction between internal and external factors light - main exogenous zeitgebers in humans - resets the body’s main ep ( scn ) - maintains the sleep wake cycle - also has indirect influence of key processes in the body which control hormone secretion and blood circulation - however, a study was done which shows that skin receptor sights may be able to detect light even when the same info is not received by the eyes - 15 ppts were awoken at various times using a light pad shone on the back of their knee - it was found that there was a deviation of their sleep wake cycle by up to 3 hours - suggests that light is a strong exogenous z but ones not rely on the eye to send influence the brain social cues - at 6 weeks our circadian rhythms begin but are pretty random - 16 weeks they b economy entrained by adult determined schedules such as bedtime and mealtime - research on jet lag also suggests that if we adapt to local times of eating and sleeping we can effectively entrain our circadian rhythms to beat jet lag

Answer 14

1. environment - exogenous zeitgebers are not effective in all environments - there are experiences of people who have little sunlight during the winter and little darkness during the summer and they have no difference - moreover, people living in the arctic circle have regular sleep schedules despite having 6 months of almost total darkness - shows that sleep wake cycles are primarily controlled by endogenous pacemakers which can override environmental changes in light 2. evidence challenging - evidence which challenges the role of exogenous zeitgebers - a recount study of a young man was done who was blind from birth and it was found he had an abnormal circadian rhythm of 24.9 hrs - despite his exposure to social cues such as regular mealtimes his sleep wake cycles could not be adjusted - this suggests that social cues alone are no effective in resetting biological rhythms

Biopsychology Flashcards

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