Ways of Investigating the Brain

Question 1

what are the four ways of investigating the brain?

Answer 1

• fMRIs
• EEGs
• ERPs
• Post-mortem

Question 2

fMRIs

Answer 2

• use magnetic fields and radio waves to detect the changes in blood oxygenation and flow that occur as a result of brain activity in specific parts of the brain
• when a brain area is more active, it consumes more oxygen so blood flow is directed to this area
• produces 3D images
• gives a moving picture of the brain
• important for understanding localisation of function

Question 3

fMRI strengths

Answer 3

• doesn’t rely on radiation
• risk free, non invasive, straightforward
• produces images with high spatial resolution
• allows active brain to be investigated during specific tasks

Question 4

fMRI weaknesses

Answer 4

• expensive, leading to small sample sizes, reducing the validity of studies
• person has to be completely still
• poor temporal resolution - 5 second lag time
• can only measure blood flow in the brain

Question 5

post - mortem

Answer 5

• the analysis of a person’s brain following their death
• person is likely to have had a rare disorder
• areas of damage within brain examined after death to establish likely cause

Question 6

post - mortem strengths

Answer 6

• evidence was vital in providing a foundation for early understanding of key processes in the brain
• broca and wernicke both relied on post-mortem studies to establish links between language, brain, and behaviour
• enable examinations of deeper regions in the brain

Question 7

post - mortem weaknesses

Answer 7

• causation is an issue
• can be affected by changes which occur during / after death
• requires special permission - small sample sizes
• ethical issues of consent
• only shows physiology, not activity

Question 8

EEGs

Answer 8

• measure electrical activities within the brain via electrodes fixed to the scalp
• detect neuronal activity directly below the electrodes
• scan recording represents brainwave patterns generated from the actions of millions of neurons, providing an overall account of brain activity
• usually used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities

Question 9

EEG strengths

Answer 9

• have proved invaluable in the diagnosis of conditions such as epilepsy
• has contributed to our understanding of the stages involved in sleep
• high temporal resolution
• cheaper than fMRIs - larger samples, increased validity
• allows active brain to be investigated

Question 10

EEG weaknesses

Answer 10

• poor spatial resolution

Question 11

ERPs

Answer 11

• use the same apparatus as EEGs but record when there’s activity in response to a stimulus
• neural responses associated with different events may be of interest to cognitive neuroscientists
• using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out, leaving only responses related to stimuli

Question 12

ERP strengths

Answer 12

• bring more specificity to the measurement of neural processes than EEGs
• high temporal resolution
• cheaper than FMRIs - large samples can be used, increasing validity
• allow active brain to be investigated

Question 13

ERP weaknesses

Answer 13

• lack of standardisation between different research studies
• background noise and extraneous variables must be eliminated
• poorer spatial resolution than fMRIs