Biopsychology: Ways of study the brain Flashcards
What is fMRI? (Functional magnetic resonance imaging)
A technique used for measuring blood flow in brain when a person performs a task
How does fMRI measure brain activity?
It works by detecting changes in blood flow that indicate increased neural activity.
How does fMRI measure blood flow?
Using radio waves and a magnetic field - magnetic field used bc oxygenated and deoxygenated blood have different magnetic qualities.
What happens if an area of the brain becomes more active?
Area more active = increased demand for oxygen in that area, bc brain uses oxygen when carrying out functions.
Brain responds by increasing blood flow, delivering oxygen in RBC’s.
Maps showing which areas of the brain are involved in a particular neural activity are produced as a result of blood flow.
Spatial resolution
smallest measurement a scanner can detect
Temporal resolution
how quickly scanner detects changes in brain activity
Advantage of fMRI - high res images
Produces high res images (accurate to a mm) so clear image of where functions are localised
Disadvantage of fMRI - poor temporal res
Poor temporal resolution because there is a 5 second time-lag behind the image on the screen and the initial firing of neuronal activity.
Worse than other techniques (EEG/ERP which have temporal res. of 1-10 milliseconds)
Consequently, psychologists unable to predict to a high degree of accuracy the onset of brain activity
Advantage of fMRI - non-invasive
Non-invasive
Unlike, PET scans, fMRI doesn’t use radiation or involve inserting instruments directly into the brain, therefore virtually risk free
Consequently, allows more patients to undertake fMRI scans
Could help psychologists gather further data on the functioning of the human brain
Therefore, develops understanding of localisation of function.
Disadvantage of fMRI - costs
Expensive compared to other imaging techniques – requires equipment and trained experts
Post-mortem examinations
Researchers study an individual’s brain post-death who displayed a behaviour which suggested possible underlying brain damage when alive
Post-mortem advantage
Vital during the early days of psychology before technology was developed e.g Broca and Wernicke
Post-mortem disadvantage - cause and effect
Cause and effect is an issue; the differences observed can be unrelated to the behaviour, possibility of damage being cause by unrelated trauma or decay
Post-mortem disadvantage - unethical
Ethical issues of informed consent.
Patients may not be able to provide informed consent, e.g in the case of HM – he was unable to form new memories and was not able to provide consent.
EEG
measures patterns of electrical activity within the brain
