ways of studying the brain: post mortem examinations Flashcards
what is a post mortem examination?
A post-mortem examination is when researchers study the physical brain of a person who displayed a particular behaviour while they were alive that suggested possible brain damage.
what did Iverson find in post-mortems of schizophrenic individuals?
examined the brain of deceased schizophrenic patients and found that they all had a higher concentration of dopamine, especially in the limbic system compared with brains of people without schizophrenia.
how did Broca use post mortem examinations to to examine speech problems?
An example of this technique is the work of Broca, who examined the brain of a man who displayed speech problems when he was alive. It was subsequently discovered that he had a lesion in the area of the brain important for speech production. This area later became known as Broca’s area.
how did Wernike use post mortem examinations to look into language comprehension?
Similarly, Wernicke discovered a region in the left temporal lobe which is important for language comprehension and processing now known as Wernicke area.
what do post mortem allow for more detailed examinations of?
Post mortem studies also allow for a more detailed examination of anatomical and neurochemical aspects of the brain and they enable researchers to examine deeper regions of the brain such as the hypothalamus and hippocampus which is not as easy with other methods of investigation.
AO3: how is ‘causation’ a limitation to post-mortems as a way of studying the brain?
one limitation of post mortem examinations as a way of investigating the brain is the issue of causation. This is because the deficits a patient displays during their lifetime such as the inability to speak, may not be linked to the deficits found in the brain such as damage to Broca’s area. Therefore, the psychologists are unable to conclude that the deficit is caused by the damage found in the brain as the deficits reported could be the result of another illness.
AO3: how is ‘extraneous variables’ a limitation to post-mortems as a way of investigating the brain?
one limitation to post mortem examinations as a way of investigating the brain is that there are many extraneous factors that can affect the results/conclusions of post-mortem examinations. For example, people die at different stages of life for a variety of reasons. This means that any medication an individual may be taking, their age at which they died and the time between the post-mortem examination can impact the findings of the research. Therefore, we have to question research in which post-mortems are used due to all the confounding factors that may occur.
AO3: how is ‘detailed examinations of the brain’ a strength to post-mortems as a way of investigating the brain?
one strength to post mortems as a way of investigating the brain is that they provide detailed examinations of the anatomical and neurochemical aspects of the brain. This is because they can access other areas of the brain such as the hippocampus and hypothalamus compared to other scanning techniques such as EEGs, ERPs and fMRIs. For example, Iverson found a higher concentration of dopamine in the limbic system of patients with schizophrenia which has prompted a whole area of research looking into the neural correlates of this disorder. Therefore, this provides researchers with an insight into these deeper brain regions which often provide a useful basis for futher research.
AO3: how is ‘ethical issues’ a limitation to post-mortems as a way of investigating the brain?
one limitation to post mortem examinations as a way of studying the brain is that there is ethical issues. This is because there needs to be informed consent from the patient before there death as it is in invasive way of investigating the brain. This is an issue as post mortems are usually carried out on individuals who have severe psychological deficits and are therefore unable to provide informed consent, such as HM who suffered from severe amnesia, even though a post mortem has eventually been carried out on their brain. Therefore, this makes us question the ethics surrounding the nature of such investigations.
