WAYS OF INVESTIGATING THE BRAIN Flashcards
what 4 ways are there for investigating the brain?
functional magnetic resonance imaging fMRI
electroencephalogram EEG
event-related potentials ERPs
post-mortem examinations
what do fMRI’s do?
detect changes in blood oxygenation and flow as result of neural activity in the brain
what happens when an area in the brain is more active during fMRIs?
increased demand of oxy, so blood flow is directed to the area
what is it called when blood flow is directed towards and active area in fMRIs?
haemodynamic response
what do fMRIs produce?
3D images showing which parts of the brain are involved in a particular mental process, having important implications for understanding` of localisation of function
what do EEGs measure?
electrical activity within the brain through electrodes fixed to someone’s skull on a skull cap
what does the scan recording during EEGs represent?
brainwave patterns that are generated from actions of neurons, providing overall account of activity in the brain
how are EEGs often used?
by clinicians as a tool for unusual arrhythmic patterns of activity which can indicate neurological abnormalities such as epilepsy, tumours or disorders of sleep
what are ERPs?
statistical averaging done on EEGs leaving responses that relate to specific stimulus or task
ERPs are defined as…
types of brainwave triggered by particular events
post-mortem examinations are…
a technique involving the analysis of person’s brain after their death
who are the individuals who are subject to a psot-mortem?
those with a rare disorder and experienced unusual deficits in mental processes or behaviour during their lifetime
what can post-mortem examinations consider?
a comparison with a neurotypical brain to see the extent of different in areas of damage afflicted
strengths of fMRIs
+ radiation free
+ risk and invasion free, making it straightforward to use
+ resolution, high spatial resolution, shows by mm showing localisation
weaknesses of fMRIs
ROT
- really expensive comp to other tech, perfect image if still
- only measure blood flow, don’t know real meaning
- temporal resolution is low as 5 sec lag
strengths of EEGs
+ shows random bursts of energy e.g. epilepsy, so invaluable for diagnosis
+ single millisecond, so high temporal resolution as we can accurately detect brain activity
+ stages of sleep contributed to our understanding
weaknesses of EEGs
- poor generalisability, nature of info received is generalised which is thousands of neurons
- poor spatial resolution, doesn’t allow researchers to distinguish activities originating in different but adjacent locations
- pinpointing, cannot do it so can’t exact source of neural activity
strengths of ERPs
+ more specificity to measurement of neural processes, using raw EEG data
+ high temporal resolution, esp when comparing to neuroimaging techniques
+ identify many types of ERP and describe the precise role of the in cog func e.g. P300 component involved in allocation of attentional resources and maintenance of WM
weaknesses of ERPs
- lack of standardisation in ERP methodology between diff research studies, difficult to confirm findings
- establish pure data in ERP studies, background noise and extraneous material needs to be eliminated and not easy to achieve
strengths of post-mortem examinations
+ vital in providing a foundation for early understanding of key processes in the brain
+ Broca and Wernicke used post-mortem studies to link language, brain and behaviour before neuroimaging was possibility
+ improve medical knowledge and help generate hypotheses for further study
weaknesses of post-mortem
- observed damaged may not be linked to the deficits under review, but due to trauma or decay
- raise ethical issues of consent before an individuals death, some may not be able to provide informed consent e.g. HM
