A2 Biopsychology - Techniques Of Investigating The Brain

Question 1

Describe fMRI

Answer 1

fMRI (functional magnetic resonance imaging) detects changes in blood oxygenation and flow due to neural activity - if a part of the brain is more active then it requires more oxygen so more blood flow to that area (called the haemodynamic response)

Produces 3D moving images called activation maps.

Question 2

Evaluate fMRI

Answer 2

(+) No radiation is used so the procedure is virtually risk free and good for use on children, whose brains are always changing.
(+) High spatial resolution; mm by mm detail
(-) Poor temporal resolution; 5 second time lag
(-) Procedure is very expensive
(-) Patient must remain perfectly still for the entire duration of the procedure so may not be suitable for children
(-) Only shows blood flow and oxygenation but not what type of brain activity is going on.

Question 3

Describe post-mortem research

Answer 3

The brain of a deceased patient who had a severe condition is examined and compared with a neurotypical brain to establish key differences and consequently a likely cause.

Question 4

Evaluate post-mortem research

Answer 4

(+) Was extremely important in the early stages of brain research before more sophisticated techniques like fMRI, EEG and ERPs were developed; Broca and Wernicke’s areas were established using this method.

(-) May be lack of informed consent; if patient is not in a fit state of mind to make an informed decision, then this type of procedure may be ethically flawed.

(-) Correlation not causation; post mortems do not tell us whether the atypical brain structure caused the condition or whether the brain structure changed over time due to the condition or even the treatment.

Question 5

Describe EEGs

Answer 5

EEGs (electroencephalograms) use a skull cap to attach electrodes to a patient’s scalp.

This records electrical activity in the brain - brainwave patters caused by the actions of millions of neurons, which gives an overall account of brain activity

EEGs provide the “raw, unprocessed” data

Question 6

Evaluate EEGs

Answer 6

(+) Very useful in the diagnosis of epilepsy - caused by short, random bursts of brain activity.

(+) Aids our understanding of the stages of sleep

(+) Very high temporal resolution; lag time of around 1 millisecond

(-) Only gives an overall account of brain activity so cannot pinpoint the cause of a particular behaviour/ condition.

Question 7

Describe ERPs

Answer 7

ERPs (event related potentials) use a statistical averaging technique to filter out all of the unnecessary data from EEGs and just be left with the relevant stuff - called the event related potential.

Question 8

Evaluate ERPs

Answer 8

(+) Very high temporal resolution as they are derived from EEGs.
(+) Much more specific than EEGs; P300 component is linked to the allocation of attentional resources and the maintenance of the working memory model.
(-) Must get rid of all background noise for pure ERP data which can be difficult and impractical.
(-) Lack of standardisation between research involving ERPs so the findings are difficult to confirm.