ways of investigating the brain

Question 1

what’re the 4 methods of investigating the brain

Answer 1

fMRI
EEG
ERP’s
Post-Mortem Examinations

Question 2

how do fMRI’s work

Answer 2

•measures changes in blood flow to particular areas of the brain, indicating increased neural activity in those areas by using radio waves and a magnetic field. more active areas have increased demand for oxygen
•increased oxygen demands met by increased blood flow (oxyhemoglobin)
•participant alternates between performing a task and a control state, producing a matching pattern of change with cause-and-effect that can be mapped

Question 3

2 strengths of fMRI

Answer 3

no reliance on radioactive tracers such as in PET scans, risk free and non-invasive

high resolution images accurate to the mm, providing clear localisation

Question 4

3 weaknesses of fMRI

Answer 4

expensive for NHS (>£1,000,000 cost requiring equipment and trained experts)

patient must stay still (inappropriate for disabled and young children)

indirect (measures blood flow rather than neuron firing, 5s delay between neuron firing and activity detected), not real time and poor ‘temporal resolution’

Question 5

how do EEG’s work

Answer 5

Electrodes on the scalp detect small electrical charges off of brain cell activity and are graphed over time, producing a graph called an EEG.

Can detect brain disorders (eg epilepsy) or to diagnose other disorders that influence brain activity (eg alzheimer’s)

Often used as a diagnostic tool

Question 6

2 EEG strengths

Answer 6

extreme usage for wide ranges of issue investigations eg sleep disorders or epilepsy

high temporal resolution (<1 ms detection of electrical activity)

Question 7

2 EEG weaknesses

Answer 7

only shows neurons firing, too weak to pickup individual neuron’s small signals, only a general measure

cannot differentiate when different but adjacent areas fire

Question 8

what are ERP’s

Answer 8

•uses EEG’s but integrated a statistical averaging technique to isolate responses, as original EEG extraneous brain activity is filtered out leaving only responses that relate to the representation of specific stimulus/task (event related potentials)
•comes in many different forms

Question 9

2 ERP strengths

Answer 9

more specific than raw EEG

Excellent temporal resolution (<1ms)

Question 10

2 ERP weaknesses

Answer 10

not standardised, difficult to replicate/compare findings from differently adopted procedures

difficult to achieve as all extraneous interface must be removed to be successful

Question 11

what’re post-mortem examinations

Answer 11

•used to establish underlying neurobiology of particular behaviours
•brains are examined after death to examine abnormalities, e.g. Broca’s research with Tan, who had Broca’s aphasia and could only say “tan” and had lesions in the modern day broca’s area

Question 12

2 post-mortem examination strengths

Answer 12

improves medical knowledge and helps generate hypotheses for further study

vital to early psychology before technology was invented (Broca/Wernicke)

Question 13

2 post-mortem examination weaknesses

Answer 13

consent is an issue (HM), needed from relatives quickly which may be problematic

dead brain differences may be irrelevant to the behavioural symptom in question, leading to inference rather than cause-and-effect