Ways Of Studying The Brain

Question 1

What are the four ways of studying the brain?

Answer 1

• Post Mortem
• fMRI (functional magnetic resonance imaging)
• EEG (electroencephalogram)
• ERP (event related potential)

Question 2

Describe a post mortem

Answer 2

• Post mortem (after death) examinations are when a persons brain is examined after they have died
• this can be used to see where damage has occurred and how that might explain behaviour exhibited by the person prior to their death
• for example, in Alzheimer’s disease damage can be seen to the areas of the brain involved in memory and language
• in modern post mortem exams, the brain can be sliced into thin sections and studied on a microscope to detect abnormalities

Question 3

What are two strengths of a post mortem?

Answer 3

• allow detailed examination of the anatomical aspects of the brain that is not possible with non invasive techniques
• Harrison (2000) suggested that structural and neurochemical abnormalities linked to schizophrenia were first identified using this method

Question 4

What are two weaknesses of a post mortem?

Answer 4

• retrospective method so it may be hard to make comparisons with functioning before death
• as soon as oxygen is cut off from the brain the shape and structure of many parts change so findings may lack accuracy -> lower levels of validity

Question 5

Describe a fMRI

Answer 5

• uses strong magnetic and radio waves to monitor blood flow in the brain
• it takes repeated scans (usually per second) to create an image of the concentration of oxygen in the blood at any given time
• areas of high activity will show correspondingly high levels of blood oxygenation and flow
• this allows sections of the brain that are active during different tasks to be identified

Question 6

What are two strengths of a fMRI?

Answer 6

• this provides a moving picture of brain activity rather than just the bland physiology of the brain. This is highly valuable when trying to link brain activity to key behaviours
• it is non-invasive and doesn’t expose the brain to potentially harmful radiation as could be found in other brain scanning devices -> ethical method

Question 7

What are two weaknesses of a fMRI?

Answer 7

• the complexity of brain activity means interpreting the scan is quite complex and problematic -> needs training but is still objective
• it focuses only on localised activity of the brain so may not identify important ways in which communication between different regions affects mental functioning

Question 8

Describe an EEG

Answer 8

• a recording of brain activity
• small sensors are attached to the scalp to pick up the electrical signals produced when brain cells communicate
• measures amplitude and frequency of the electrical activity in the brain and identifies patterns in activity that may be associated with certain states, this means it can help identify abnormalities in those areas
• a particular use is to detect and investigate epilepsy

Question 9

What are two strengths of a EEG?

Answer 9

• can be used effectively in clinical practice to study sleep disorders, identify disturbed brain activity and help with diagnosis
• this is cheaper than many other methods of studying the brain so is used more extensively

Question 10

What are two weaknesses of a EEG?

Answer 10

• the output from the machine needs to be interpreted and a high level of expertise is required to use this method effectively
• electrical activity can be picked up by several neighbouring electrodes therefore the signal is not useful for pinpointing the exact source of activity and is only useful for showing general activity levels

Question 11

Describe a ERP

Answer 11

• use a similar array of recording electrodes as an EEG but it measures electrical response to a specific stimulus
• in order to identify small specific responses it is necessary to take recordings from numerous presentations then average out the responses to obtain an event related potential
• often used when investigating fast responses that might not get detected by other investigative techniques such as fMRI

Question 12

What are two strengths of a ERP?

Answer 12

• useful to measure the reliability of self-reported techniques, especially when the topic being investigated is sensitive and likely to be effected by social desirability bias
• it can directly measure neuronal activity and give the earliest indications conscious cognitive processing. This is because it can detect the slightest changes due to any environmental manipulation of stimuli

Question 13

What are two weaknesses of a ERP?

Answer 13

• the output from the machines needs to be interpreted and a high level of expertise is required to use this method effectively
• it only detects strong voltage changes across the scalp. Important electrical activity deep in the brain are not recorded, hence this method is limited to just the neocortex