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ways of studying the brain - Coggle Diagram
ways of studying the brain
electroencephalogram (eeg)
= a method used to measure electrical impulse activity in the brain via electrodes that are fixed to an individual's scalp using a skull cap
the scan recording shows the brainwave patterns that are generated from the actions of thousands of neurons
often used by clinicians as a diagnostic tool, as unusual arrhythmic patterns of activity may indicate neurological abnormalities eg epilepsy
functional magnetic resonance imaging (fmri)
= a method used to measure brain activity when someone is performing a task
detects changes in both blood oxygenation & flow, that occur as a result of neural activity in specific parts of the brain
brain area more active = consumes more oxygen & to meet this increased demand, blood flow is directed towards the active area (the haemodynamic response)
detects radio waves from changing magnetic fields
produces 3-dimensional images known as activation maps, showing which parts of the brain are involved in particular mental processes
event-related potentials
(erp) = the electrophysiological response of the brain to a specific sensory, cognitive or motor event can be isolated through statistical analysis of eeg data
uses similar equipment to eeg
a stimulus is presented to a participant & the researcher looks for activity related to that stimulus
the responses identified in eegs are isolated in erps
through statistical averaging, all extraneous brain activity from the original eeg is filtered out, leaving only those responses that relate to the presentation of a specific stimulus/performance of a specific task
research has revealed many different forms of erp & how, for example, these are linked to cognitive processes such as attention & perception
post-mortem examinations
= the brain is analysed after death to determine whether certain observed behaviours during the person's lifetime can be linked to structural abnormalities in the brain
brains subject to this = likely to be those who have a rare disorder & have experienced unusual deficits in cognitive processes/behaviour during their lifetime
may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference
evaluation
strengths
eeg has good temporal resolution in comparison to fmri
this refers to the accuracy of the scanner in relation to time
eeg scanners take readings every millisecond, meaning it can record brain activity in real time
but fmri has a temporal resolution of 1-4 seconds
suggests eeg can provide a high level of accuracy when examining brain activity, allowing psychologists to draw accurate conclusions in comparison to fmri
fmri has good spatial resolution in comparison to eeg
this refers to the smallest feature that a scanner can detect
greater spatial resolution allows psychologists to discriminate between different brain regions with greater accuracy
fmri has a spatial resolution of around 1-2mm, which is significantly greater than the other techniques
but, eeg can only detect activity in superficial regions of the brain
therefore, psychologists can determine the activity of different brain regions with greater accuracy when using fmri in comparison to eeg, making it an ideal choice for pinpointing brain regions
limitations
an issue with both fmri & eeg is that they don't show causation
fmri don't provide a direct measure of neural activity, they simply measure changes in blood flow, therefore its impossible to infer causation
eeg detects electrical activity in several areas of the brain simultaneously
consequently, psychologists can't conclude whether particular brain regions are associated with specific functions in the case of fmri, & which area the electrical activity took place in the case of eeg, making solid cause-and-effect conclusions impossible