Ways of investigating the brain Flashcards
what are fMRIs?
detects changes of both blood oxygenation and flow that occurs due to brain activity in specific parts of brain
what do fMRIs produce?
3-dimensional images showing parts of brain involved in specific mental processes. shows activity 1-4 secs after something occured + accurate within 1-2mm
strengths of fMRIs
- non-invasive: risk free, doesnt use radiation like PET
- very high spatial resolution: detail by milimetre
- clear picture of how brain activity localised
- prac apps in medical settings eg brain surgeries
limitations of fMRIs
- expensive compared to others, only capturing clear image if person still or blurry
- poor temporal resolution: 5 sec time-lag so cant say when sm happens so not rep momemnt to moment brain activity
what are PETs?
technique to analyse person’s brain following their death, people likely to be those with rare disorders/unusual deficits
what do PET show?
areas damaged within brain examined to establish likely cause of person’s experience + compare to neurotypical to calrify extent of difference
strengths of PET
- helps understand key processes in brain: led to devel of Broca + Wernicke’s areas
- used to study HM, provide useful info
- improve medical knowledge so generate hypotheses for further studies
limitations of PET
- lack causation: damage may not be due to deficits but related to trauma/decay
- ethical issues: consent eg HM couldnt form memories so no consent, challenges usefulness
what are ERPs?
event related potentials- types of brainwave that are triggered by particular events
what do ERPs do?
- using statistical averaging technique all extraneous brain activity from EEG recording filtered out leaves responses relating to presentation of specific stimuli. leaving ERPs
strengths of ERP
- temporal resolution compared to fMRI, take readings every milisecond so real time brain activity instead of passive brain
- used to measure cognitive functions + deficits eg maintence of WM
- specific measurement of neural processes
limitations of ERPs
- lack of standardisation makes difficult confirming findings
- extraneous material must be completely eliminated eg background noise to get pure data which isnt easy to achieve
- low spatial resolution as only focuses on time brainwave is stimulated
what are EEGs?
measure electrical activity in brain via electrodes fixed to individuals scalp using skull cap
what do EEGs record?
brainwave patterns generated by thousands of neurons. often used by clinicians as diagnostic tool eg epilepsy/sleep disorders
strengths of EEGs
- invaluable diagnosing conditions eg epilepsy- random bursts of activity in brain
- contributed to understanding of stages of sleep
- high temporal resolution as detects brain activity at resolution of single milisecond so real world usefulness
- non-invasive as directly over surface of brain
- cheaper compared to fMRI so less strain on NHS
limitations of EEGs
- info is recieved from many thousands of neurons, generalised signal
- difficult to know exact source of neural activity so has low spaital activity as cant distinguish where functions localised
