ways of investigating the brain

Question 1

fMRI

Answer 1

• detects changes in blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain
• when a brain area is more active if consumers more oxygen and to meet this demand blood flow is directed to the active area
• produces 3D images showing which parts of the brain are involved in a particular mental processes

Question 2

EEG

Answer 2

• measure electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap
• the scan recording represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity
• used as a diagnostic tool, can indicate neurological abnormalities such as tumours

Question 3

ERPs

Answer 3

using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out leaving only those responses that relate to for example the presentation of a specific stimulus or performance of a specific task
-ERPs remain, types of brainwave that are triggered by particular events

Question 4

post-mortem examinations

Answer 4

• analysis of a persons brain following their death

- areas of damage are examined as a means of establishing the likely cause of the affliction the person suffered

Question 5

evaluation of fMRIs

Answer 5

strength:

• doesn’t rely on the use of radiation
• virtually risk free, non invasive and straightforward to use
• produces images that have a high resolution
• provides clear image of his brain activity is localised

weakness:

• expensive
• can only capture a clean image if patient stays perfectly still
• poor temporal resolution (5 sec lag between the image on screen and initial firing of neuronal activity)
• can only measure blood flow in the brain not activity of individual neurons so it can be difficult to tell exactly what kind of brain activity is being represented

Question 6

evaluation of EEG

Answer 6

strengths:

• invaluable in diagnosis of conditions such as epilepsy
• contributed to our understanding of the stages involved in sleep
• can accurately detect brain activity at a resolution of a single milisecond

weaknesses:

• not useful for pinpointing the exact source of neural activity
• doesn’t allow researchers to distinguish between activities originating in different but adjacent locations

Question 7

evaluation of ERPs

Answer 7

strengths:
-excellent temporal resolution

weaknesses:

• difficulties to confirm findings
• lack of standardisation between different research studies
• background and extraneous material must be completely removed which may not always be easy

Question 8

evaluation of post mortem examinations

Answer 8

strengths:

• vital in providing a foundation for early understanding of key processes in the brain
• broca and wernicke relied on PME in establishing links between language, brain and behaviours
• improve medical knowledge and help generate hypotheses for further study

weaknesses:

• observed damage to the brain may not be linked to the deficits under review but to some other unrelated trauma or decay
• raise ethical issues of consent from the patient before death