Ways of studying the brain Flashcards
Functional magnetic resonance imaging (fMRI)
Ways of studying the brain
Works by detecting changes in blood oxygenation & flow that occur as result of neural activity in specific parts of the brain
When a brain area is more active it consumes more oxygen & to meet this increased demand, blood flow is directed to active area
fMRI produces 3D images showing which parts of brain are involved in particular mental processes
Has important implications for our understanding of localisation of function
Electroencephalogram (EEG)
Ways of studying the brain
Measures electrical activity w/in brain via electrodes fixed to individual’s scalp using skull cap
Scan recording represents brainwave patterns generated from action of thousands of neurons, providing overall account of brain activity
EEG used by clinicians as diagnostic tool as unusual arrhythmic pattersn of activity may indicate neurological abnormalities such as epilepsy
Event-related potentials (ERPs)
Ways of studying the brain
EEG in raw form is overly general measure of brain activity
W/in EEG data are contained all neural responses associated w/ sensory, cog & motor events that may be of interest to cog neuroscientists
Researchers developed way of isolating these reponses
Using a stats averaging technique, all extraneous brain activity from og EEG is filtered out leaving wanted repsonses
What remains are ERPs - types of brainwave triggered by particular events
Post-mortem examinations
Ways of studying the brain
Technique involving analysis of person’s brain following their death
Individuals whose brains are subjects to post-moterm are likely those who have rare disorder & have experienced unusual deficits in cog processes or behaviour
Areas of damage w/in brain are examined after death as means of establishing likely cause of affliction person experienced
May also involved comparison w/ a neurotypical brain in order to ascertain extent of difference
Evaluation: fMRI strengths
Ways of studying the brain
fMRI doesn’t rely on radiation
If administered correctly it is virtually risk-free, non-invasive & straightforward
Produces images w/ high spatial resolution, depicting detail by the mm & providing a clear picture of how brain activity is localised
Means fMRI can safely provide clear picture of brain
Evaluation: fMRI limitations
Ways of studying the brain
Expensive compared to other neuroimaging techniques
Has poor temporal resolution as there is 5s time-lag behind image on screen & inital firing of neuronal activity
Means fMRI may not truly represent moment-to-moment brain activity
Evaluation: EEG strength
Ways of studying the brain
Useful in studying stages of sleep & in diagnosis of conditions such as epilepsy
Unlike fmRI, EEG tech has extremely high temporal resoluation
Can accurately detect brain activity at resolution of single millisecond
Shows real-world usefulness of technique
Evaluation: EEG limitations
Ways of studying the brain
Generalised nature of info received
EEG singal is not useful for pinpointing exact source of neural activity
Therefore, doesn’t allow researchers distinguish between activities originating in diff but adjacent locations
Evaluations: ERP strengths
Ways of studying the brain
Limitations of EEG are addressed through use of ERPs
Beings more specificity to measurement of neural processes than could be achieved using raw EEG data
As ERPs are derived from EEG measurements, the have excellent temporal resolution, especially compared to fMRIs
Means ERPs are used to measure cognitive functions & deficits such as allocation of attentional resources & maintenance of working memory
Evaluation: ERP limitations
Ways of studying the brain
Lack of standardisation in ERP methodology between diff research studies which makes it difficult to confirm findings
To establish pure data in ERP studies, background ‘noise’ & extraneous material must be elimanted
This is not always easy to achieve
Evaluation: Post-mortem strengths
Ways of studying the brain
Vital in providing foundation for early understanding of key processes in brain
Broca & Wernicke relied on post-mortem to establish links between language, brain & behaviour decades before neuroimaging was possible
Post-mortem used to study HM’s brain to identify areas of damage, which could be associated w/ memory deficits
This means post-mortems continue to provide useful info
Evaluation: Post-mortem limitations
Ways of studying the brain
Causation is an issue
Observed damage to brain may not be linked to deficits under review but to other unrelated trauma or decay
Ethical issues of consent from individual before death
Ppts may not be able to provide informed consent (e.g. HM)
Challenges usefulness of post-mortem studies in psychological research
