ways of studying the brain Flashcards
what is the purpose of investigating and scanning the brain?
- medical purposes in diagnosis of illness
- investing localisation in psychological research
what are 4 ways of studying the brain?
- functional magnetic resonance imaging (fMRI)
- electroencephalogram (EEG)
- event-related potentials (ERPs)
- post-morten examinations
how do fMRIs work?
by detecting changes in blood oxygenation and flow that occur due to neural activity in specific parts of the brain
what is the haemodynamic response?
- when a brain area is more active, it consumes more oxygen
- to meet this increased demand, blood flow is directed to the active area
what type of images do fMRIs produce?
- 3D images
- activation maps show which parts of the brain are involved in a particular mental process (LOF)
what do EEGs measure?
electricity activity in the brain via electrodes that are fixed to an individual’s scalp using a skull calp
what does an EEG scan recording represent?
- brainwave patterns from the action of thousands of neurons
- provides an overall account of brain activity
what are EEGs used for?
- diagnostic tool for unusual arrhythmic patterns of activity (ie. no particular pattern)
- may indicate neurological abnormalities such as epilepsy, tumours or some sleep disorders
how can researchers isolate specific electrophysiological responses?
- statistical average technique
- all extraneous activity from original EEG recording is filtered out
- leaves only responses related to eg. specific sensory, cognitive or motor event
what are ERPs?
types of brainwave that are triggered by particular events
what do post-mortem examination techniques involve?
analysis of a person’s brain following their death
what type of individuals may have their brain subject to PME in psychological research?
- have a rare disorder
- experienced unusual deficits in cognitive processes or behaviour during their lifetime
what do PMEs involve?
- examining areas of damage in the brain to establish likely cause of affliction the person experienced
- compare with neurotypical brain to find extent of difference
fMRI: strengths (7)
- don’t need to use radiation, unlike PETs
- virtually risk-free if done correctly
- non-invasive
- straightforward to use
- gives images with very high spatial resolution, depicting detail by the millimetre
- provides a clear picture of how brain activity is localised
- used in lie detection due to its ability to see inside the brain
fMRI: limitations (2)
- expensive compared to other neuroimaging techniques
- poor temporal resolution due to 5s time-lag behind image on screen and initial firing of neuronal activity
EEG: strengths (3)
- useful in studying stages of sleep
- used in diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of acitivty in the brain that can easily be detected on screen
- extremely high temporal resolution (1 ms or less)
EEG: limitations (3)
- information received is generalised
- not useful for pinpointing exact source of neural activity
- does not allow researchers to distinguish between activities originating in different but adjacent locations
ERP: strengths (4)
- addresses limitations of EEG
- bring more specificity to measurement of neural processes than could be achieved using raw EEG data
- excellent temporal resolution
- can be used to measure cognitive functions and deficits eg. allocation of attentional resources and maintenance of working memory
ERP: limitations (2)
- lack of standardisation in ERP methodology between different research studies, making it difficult to confirm findings
- to establish pure data in ERP studies, background ‘noise’ and extraneous material must be completely eliminated, which may not always be easy to achieve
PME: strengths (3)
- vital in providing foundation for early understanding of key processes in the brain
- eg. broca and wernicke both relied on PM studies to establish links between language, brain and behaviour before neuroimaging became a possibility
- used to study HM’s brain to identify areas of damage which could be associated with his memory deficits
PME: limitations (4)
- causation is an issue
- observed damage to brain may not be linked to deficts but to other unrelated trauma or decay
- raise ethical issues of consent from individual before death
- participants may not be able to give informed consent eg. HM lost is ability to form memories so couldn’t provide consent, but his brain was researched anyway
