ways of studying the brain Flashcards
Functional magnetic resonance imaging (fMRI)
- identifies changes in levels of oxygen in blood
- that occur due to brain activity in specific areas
- when brain area is more active - more oxygen being used - increase blood flow to this area
- produces 3D image
- shows which part of brain is active (activation map)
- used to identify specific parts of brain active in specific mental processes
AO3 for fMRI: Strength - safe technique
P- fMRI much safer technique measure brain activity
E - non-invasive - does not use radiation to identify differences in brain areas
E - unlike use of PET scans - use radiation
L - so fMRI more appropriate technique - could reduce risk of potential harm to individuals
AO3 for fMRI: Spatial and temporal
P - fMRI have higher spatial resolution than EEG + ERP - important feature of brain scans
E - as accurately identifies specific brain areas involved in behaviour - depicting detail by the mm - provide clear image of how brain localised
E - however, fMRI poorer temporal resolution - as there is around 5 second time lag behind image on screen and initial firing of neuronal activity
L - so fMRI’s not truly represent moment-to-moment brain activity
Electroencephalograph (EEG)
- electrodes placed on the scalp using skull cap
- detect small electrical changes from activity of brain cells
- electrical signals graphed over period of time
- show person’s general brain activity
- used to detect sleep patterns and states e.g. sleep/arousal
- uses diagnostic tool to help diagnose conditions e.g brain tumours and epilepsy
AO3 for EEG: Strength - temporal
P - strength using EEG - high temporal resolution
- allows researcher take real time recording of brain activity - rather than still image of brain (fMRI or post-mortem)
E - can gain more accurate measure of brain activity for specific task
L - so provides greater insight into processes of brain e.g. activity of brain during sleep - increasing validity as way of studying brain
AO3 for EEG: Limitation - spatial
P - limitation using EEG - low spatial resolution
E - only provide info on general brain activity - cannot pinpoint exact source of neural activity involved in behaviour
E - unlike ERPs which identify specific brain activity in particular task
L - so findings less valuable in developing our understanding than using other ways of scanning brain
Event-related potentials (ERPs)
- like EEG - electrodes placed on scalp
- unlike EEG - shows specific brain activity
- stimulus presented to individual many times
- brain activity is measured
- however, all extraneous brain activity filtered out
- leaving only responses linked to presentation of stimulus
- what remains once extraneous brain activity filtered = ERPs = types of brainwave triggered by particular event
AO3 for ERPs: Temporal and spatial
P - ERPs have high temporal resolution - especially compared to fMRI
E - ERPs can identify brain activity every millisecond - so researcher see brain activity in real time
E - however, ERPs poorer spatial resolution than fMRI - can only detect brain activity in general brain areas
L - rather than identify specific location of brain activity
AO3 for ERPs: Limitation - meaningful data
P - hard to obtain meaningful data from use of ERPs
E - as can be affected by external factors e.g. background noise
E -so can take many trials to obtain meaningful data as hard to control other factors
L - limits validity of ERPs as way of studying brain for range of brain processes
Post-mortems
- brain of dead patient is examined and dissected
- see if are any physical/structural abnormalities
- brain compared with brain that does not show particular behaviour or mental process
- mainly used on ppl have rare disorder or defects
- one area of research - identification Broca’s area- for speech production
AO3 for Post-mortems: Strength - detailed
P - only invasive way to study brain
E - is possible to get more detailed examination of brain than through solely using brain scanning techniques e.g ERPs and EEG
E - for example - researchers able to study deeper areas of brain e.g. hypothalamus
L - helped understand brain functioning in many different behaviours
AO3 for Post-mortems: Limitation - cause and effect
P - hard to establish cause and effect with post-mortems
E - as many confounding variables
E - which can’t be controlled easily e.g. how long person had disorder, age at time of death, whether received drug treatment
L - so limits internal validity of findings of these studies - and appropriateness of using post-mortems to study brain
