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Discuss two of the following methods that have been used to investigate areas of cortical specialisation in the brain: post-mortem examinations, EEG and scanning techniques

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´╗┐Anna Shepherd, Psychology AS Jo Birnie, Room 5.01 Sunday 30th September Discuss two of the following methods that have been used to investigate areas of cortical specialisation in the brain: post-mortem examinations, EEG and scanning techniques (10 marks) A method of investigation of cortical specialisation simply addresses the technique/s in which the brain of a person has been examined, in order to give the investigator a more detailed understanding of the different parts of the brain. Over the last few decades, technology has vastly improved, and thus improved the biological psychologist?s ability to study the brain. Methods in which this is done can be either invasive or non-invasive, and all have their benefits and disadvantages. The two that I shall discuss are post-mortem examinations, and scanning techniques. Post mortem studies are research methods conducted with the main focus being the neurobiology in the brain, and the brain having belonged to a person with certain illnesses, of which have been studied whilst the subject was alive. Such diseases can include Alzheimer?s, or other afflictions such as inabilities to speak or even paralysis. All these are investigated during the post mortem, as with all other experiments, the examinations must be repeated to ascertain a valid analysis. Post mortem studies are older than any scanning techniques, and though primitive, had been used to study the relation between the brain and corresponding behaviours. ...read more.


Judaism and Islam forbid them, whilst others will allow them to occur under special circumstances. However, if the subject of the investigation belongs to a religion that decrees post mortem as forbidden, nothing can be done to examine the brain in a technique like post mortem investigations, no matter how much the information is needed for research. Furthermore, if the cause of the research is brain damage, examining the brain itself may not bring about a pinpoint conclusion as to which area is responsible. Alternatively, the rarity of the affliction needed to be studied may affect how many brains there are able to use- not everyone will have this affliction, and an even smaller percentage will adhere to post mortem examinations after death. As technology and technique in cortical specialisation investigations have improved, a greater array of scanning methods have been discovered; all with different benefits and disadvantages. Such scan types include Computerised Axial Tomography (CAT), Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI). CAT scans comprise of sending a thin X-ray beam, at different angles, through the brain, and measuring how much radiation is absorbed by it. They produce 3D images that can identify tumours and damaged tissues at a deep level. With PET scans, a small amount of radioactive glucose is injected into the bloodstream, and provides the brain with energy which is then shown onscreen whilst the subject is conscious and performing tasks. ...read more.


Also, there are health risks that are similar to the CAT scan; in general, the radiation from a typical PET scan is equivalent to about 3 to 5 times as much as a person would receive in 1 year from the naturally occurring background radiation exposure. Many do not like the closure of being in the tunnel as part of MRI equipment. If sedation is therefore used, there are risks of excessive sedation. A technologist or nurse monitors vital signs to minimize this risk, but is subject to human error. People with pacemakers cannot have MRIs and some people who are morbidly obese cannot fit in into an MRI system. Patients are given earplugs or stereo headphones to muffle the noise caused by the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise. In conclusion, both methods of investigating cortical specialisation have both advantages and disadvantages. Scanning techniques has less ethical risks than post mortems, and confronted with fewer related difficulties. However, post mortems are done after death (therefore, no risk of infection) and are as accurate as one can get. Scans are the same, but are very expensive, and many use radiation which can build up and cause many health issues. One isn?t necessarily more effective than the other, but are used in separate situations and meet different needs. ...read more.

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