AQA A Level Psychology Biopsychology

Terms in this set (23)

When a person experiences a life threatening or stressful situation the body responds with what is known as the fight or flight response. It is an evolutionary adaptive survival mechanism enabling us to react quickly to certain stimuli.
However this response now days is activated too often to non life threatening situations such as exam stress.
It works by as follows, when faced with a stressful situation the amygdala is activated a signal is then sent to the hypothalamus which uses the sympathetic nervous system to communicate with the rest of the body.
It's response to acute stress takes the sympathomedullary pathway (SAM). When the SNS is triggered it sends a signal to the adrenal medulla which releases adrenaline into the blood. The adrenaline causes the heart to beat faster allowing for more blood into the brain. After a while the parasympathetic nervous system is triggered causing the stress response to be dampened down.

After 20 minutes if the stress is continued, it is then known as chronic stress and the response is different. Instead of the sympathomedullary pathway it takes the hypothalamic pituitary adrenal system (HPA).
The hypothalamus releases the chemical corticotrophin releasing hormone into the blood stream, this arrives at the pituitary gland causing it to release adrenocorticotrophic hormone. This is then targeted at the adrenal gland, specifically the adrenal cortex, causing the release of cortisol which gives a quick burst of energy and higher pain thresholds. However it can lower both the immune system and impair cognitive performance.
:( - Research suggests that females have a different behavioural response to stress, known as tend and befriend. This is due to women's role as a PCG, they are thus more likely to protect themselves and their children through nurturing behaviours and forming alliances with other women. This suggests that therefore women may have evolved differently saying that the fight or flight response can not be applied to both genders.

:( - The flight part of fight or flight could be detrimental to the safety of women's offspring. Research conducted with rats found that women may release oxytocin which inhibits flight. This hormone has been shown to increase relaxation. This research further shows evidence for the fight or flight not being able to be applied to women.

:( - The fight or flight response is an evolutionary survival technique however modern day life can trigger this too frequently in inappropriate situations. This can be detrimental to out health and cause coronary heart disease. Furthermore too much cortisol can result in us being more prone to illness. Therefore the very process that is designed to save our lives could in fact cause illness.

:( - Research suggests that there are other responses before fight or flight. He said that humans are more interested in avoiding confrontation rather than fleeing it. This is known as the freeze response where by people are hyper vigilant and alert to any danger. The freezing focuses attention and helps people find new information in order to deal with the threat. This limits the value of insight psychologists have in accurately explaining response to stress.
:) - There is evidence that supports the localisation of function of language. Patients with damage to the areas where language centres are experience aphasia, this is an inability to understand and produce speech. Specific damage to Broca's area demonstrates the importance of this region for speech production and the same with Wernicke's area.

:( - Not all researchers agree that the brain has localisation of function. One researcher founded the equipotential theory. It states that basic motor and sensory functions are localised but higher mental functions are not and that if there is a brain injury intact areas of the rain will take over for specific functions.

:( - Some research shows us that how the brain communicate with each other is more important than the specific brain regions being responsible for functions. Wernicke stated that different brain areas must interact with each other to effectively function. This is supported by a case study done into a man who lose the ability to read which resulted from damage to the connection between the visual cortex and Wernicke's area. This suggests that complex tasks require different structures of the brain to deal with the same stimulus as opposed to localisation of function.

:( - Other research suggests that there are large individual differences in how peoples brains are activated in language activities. Research done by Harasty found that there were even gender differences in the size of the brain associated with language, and it was further found that women have proportionally larger Broca's and Wernicke's areas than men resulting in women using their language more. This therefore limits the value of the insight that psychologists have regarding the localisation functioning in the brain.
Functional Magnetic Resonance Imaging (FMRI)
This technique measures changes in the brain whilst a person is doing a task. Using a strong magnetic flux it tracks ion movement within the brain, which is within the blood. If a part of the brain becomes more active then more oxygen is required, oxygen travels within the blood and thus it links ion levels to brain activity.

Electroencephalogram (EEG)
An EEG measures electrical activity in the brain. Electrodes are places all over the scalp to detect any small electrical impulses. There are four different EEG patterns that are usually detected:
Alpha waves when awake, Beta when physiologically aroused (also seen in REM) and Delta+Theta waves seen in sleep.

Event-related Potentials (ERP)
Similar to EEG's however this looks at the brain reacting to a stimulus instead of just stand alone. It looks at very quick high voltage changes within the brain, it is difficult to isolate the other electrical activity and thus to remove background noise the target stimulus is presented many times to the patient and the response is averaged out and background noise removed. There are two types of waves occurring after presentation of stimulus: Sensory ERP's before 100ms and Cognitive ERP's after 100ms of stimuli.

Post Mortem Examinations
These are used after a patient has died to physically see the neurobiology of a particular behaviour. For example Broca's work analysing the brains of people who had speech problems led him to discover the important area responsible for speech.
FMRI
:) - Non invasive and does not expose brain to potentially harmful radiation as is the case with other scan methods

:) - Offers a more objective and reliable measure of psychological processes than is possible with verbal reports. It is a useful way of investigating psychological behaviour using a quantitative report

:( - A FMRI measures changes in ion level rather than directly measuring brain activity it is not then a direct measure of neural activity. This means it is not a truly quantitative measure of mental activity in these brain areas

:( - People argue that FMRI overlooks the networked nature of the brain and rather just looks at the localised activity. It is communication within the brain that is key, not just each area working separately

EEG
:) - An advantage of the EEG technique is that it provides a constant recording of the brains activity rather than just a still image. This means the researcher can more accurately measure brain activity in a particular task

:) - EEG's are good for clinical diagnosis for example epilepsy can be diagnosed easily as when someone is experiencing a seizure the EEG reading should suddenly change

:( - EEG's can only see what is going on in superficial areas of the brain and not the deeper regions and thus it cant see important areas such as the hippocampus

:( - Although there are many seperate electrodes as part of an EEG a lot of the time a group of electrodes will detect the spike in voltage change and thus it is hard to say exactly where the change originates from

ERP
:) - As ERP's provide a continuous measure of brain activity in response to a stimuli it makes it possible to determine exactly how a stimulus affects the brain and thus drawing a cause and effect relationship

:) - An ERP can measure the reaction to stimuli without the need for the patient to learn any techniques, and thus be fairly covert.

:( - As ERP's are so small and difficult to pick out from other electrical activity within the brain it means many trials must be done and thus this places limitations on what it can truly answer or prove

:( - Similar to EEG's, ERP's only detect significantly strong voltages and thus many of the recordings gained are only from superficial regions of the brain

Post Mortem
:) - This allows for a more detailed anatomical examination of the brain of areas that through other methods would not be possible as they are too deep within the brain, for example the hippocampus

:) - Harrison claims that post mortem studies have played an extremely important role in our understanding of schizophrenia. He suggests that as a result of pot mortem's we have discovered abnormalities within the brain that change levels of dopamine which is associated with disorders

:( - There are many confounding variables that may have affected the brain when conducting a post mortem, such as the time between death and doing it, the point at which they are at in their illness etc. This means that when extrapolating the findings it must be done with caution

:( - This technique is retrospective as the patient is already dead and thus it makes it impossible for the psychologist to follow up on anything between the physical side and the cognitive side of the patient
Circadian rhythms last approximately 24 hours with the sleep wake cycle, body temperature and hormone cycle being the best known. They are often referred to as a body clock to help animals meet the varying demands of day and night.
Circadian rhythms are driven a suprachiasmatic nuclei, located in the hypothalamus, which is known as master circadian pacemaker. This pacemaker is constantly reset by light through a process called photoentrainment, light sensitive cells within the eye detect brightness and then send this information to the SCN, which in turn controls the activity of the circadian rhythm.
The sleep wake cycle is affected by this external cue however it is also said that there is an endogenous clock that is free running and works within 24-25 hours.
Another circadian rhythm is the body temperature rhythm, its thought to be at a lowest temperature of 36 degrees at 430am and 38 degrees at 6pm.

:) - Michel Siffre conducted an experiment which provides evidence for circadian rhythms existing despite isolation from light. He spent long periods of time living in caves with no external cues and found that his natural circadian rhythm settled at just over 24 hours. Further research where participants were placed in a WWII bunker also found that their circadian rhythms stayed at between 24-25 hours

:( - However critics were quick to point out a huge flaw in his research. Although they were not exposed to natural light they were exposed to light from torches which has the same effect as natural effect. A researcher wanted to prove that fake light could act as an external zeitgeber thus they shone a torch on the back of peoples leg and found it could alter circadian rhythms between 22-28 hours. This suggests that the free running part of circadian rhythms were not properly measured

:( - An important criticism is that most of the findings into circadian rhythms are not absolute and found many different individual differences within participants varying from 13-65 hours. This suggests that there must be other factors other than a free running endogenous clock that may have effected their sleep wake cycles.

:) - Finally to overall evaluate, there are significant real world applications that research into circadian rhythms has found. Circadian rhythms has shown to directly affect digestion, heart rate and hormones, and therefore we can clearly see it can be used with Chronotheraputics which is the study of timing affects on medication. For example certain drugs that are released and consumed at times of the day where hormones are at peaks
Ultradian rhythms span for less than a day, an example would be the five stages of sleep which lasts for around 90 mins before it repeats itself.
The first two stages are light sleep with the brain producing beta and alpha waves and eventually theta when you start to fall deeper into sleep. The third and fourth stages consist of mainly delta waves resulting in the person being very difficult to wake up but still conscious, in this sleep is where its thought growth hormone is released to repair the body. The final stage, stage 5 is REM sleep with EEG activity resembling that of an awake brain.

:) - Research suggests that in REM sleep people dream. Researchers woke up participants during the night when their brain activity was characteristic of REM sleep. They found that participants were highly likely to be dreaming at this time, with some having matching eye movements in sync with the dream

:( - However these findings were not absolute as there was found to be widespread individual differences because some dreams were recorded outside REM sleep and some dreaming just didn't occur in REM sleep. This suggests that other factors may have affected their dreaming so it suggests more research is needed on topic before firm conclusions are drawn.

Infradian rhythms span over times longer than a day but less than a year, on example would be the menstrual cycle whereby ones a month females pituitary gland will release hormones which cause a follicle to ripen an egg. When the egg is ready progesterone is released to help the womb before pregnancy. After two weeks if there is no fertilisation progesterone levels decrease and the womb is shed.
Another infradian rhythm is seasonal affective disorder, which is a depressive condition during the winter months that is due to fewer hours of sunlight. It is thought that more darkness increases melatonin which makes the individual display depressive symptoms.

:( - Although the menstrual cycle is said to be an endogenous system that is naturally controlled by hormones research has shown otherwise. One researcher found that women who live together ten to synchronize their menstruation each month. Sweat from one group of women rubbed on the upper lips of another group resulted in both groups menstruating at the same time. This is due to the pheromones present in the sweat, this suggests that exogenous cues altered the women's infradian rhythm.

:( - SAD could in fact not just be an infradian rhythm but rather a disrupted circadian rhythm due to external zeitgeber's such as decreasing sunlight hours. During winter people have to get up at the same time due to school/work etc. however they may choose to sleep earlier as it will have been dark for longer. This may lead to confusing the body into thinking time is shifting and thus causing negative symptoms similar to that of jet lag.

Finally to overall evaluate there are many different real world applications that research into biorhythms has allowed for. Because of research done into SAD, phototherapy has been established, this is where strong lights are used which are person looks at during the evening to change levels of melatonin and serotonin. This therefore means that research to support biological rhythms is an important area of applied psychology which can benefit society.
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