Methods of investigating the brain

• what is a fMRI?

  -method used to meausre brain activity whilst a person is performing a task.
• what are the strengths of fMRI?

  -it doesn't use radiation

  -basically risk free, non-invasive and straight forward to use.

  -produces images that have high spatial resolution, depicting detail by the mm and providing a clear picture of how brain activity is localised.
• what are the weaknesses of fMRI?

  -expensive

  -person must stay perfectly still

  -poor temporal resolution because theres a 5 second time lag.

  -only measure blood flow in the brain
• what is a electro-encephalogram (eeg)

  -electrodes are fixed to an individual's scalp using a 'skull cap'.

  -it measures electrical impulses from neural action and gives an overall account of brain activity.
• whats a strength of EEG's

  -invaluable in diagnosis of conditions like epilepsy.

  -contributed to our understanding of the stages of sleep.

  -it has high temporal resolution.
• whats a weakness of EEG?

  -you get info on many thousands of neurons all at once so is a very generalised picture of brain activity so doesnt pinpoint the exact source.
• what are ERP's?

  -an advancement on the EEG.

  -developed a way to isolate the response to a specific stimulus, by using a statistical averaging technique they can filter out all extraneous brain activity.
• what is a strength of ERP's?

  brings more specificity to the the measurement of neural processes than EEG's.

  have excellent temporal resolution.
• what is a weakness of ERP'S

  -a lack of standardisation in different ERP methodology between different research studies makes it difficult to confirm findings.

  -all background noise and extraneous material must be completely eliminated and this can be difficult to achieve.
• what are post mortems?

  -the brain is analysed after death by empowering and dissecting it to determine whether observed behaviours in life correspond with physical abnormalities in the brain.
• what is a strength of post mortems?

  -was vital in providing a foundation for our early understanding of the brain.

  -broca and wernickes both relied on post mortem studies.

  -they improve medical knowledge and help general hypothesis.
• what are the weaknesses of post mortems?

  -observed damage may not be linked to the deficits being looked at so there is an issue of causation.

  -done after death so it doesnt benefit that person.

  -ethical issues.