Scanning Techniques Flashcards
fMRI - functional magnetic resonance imaging
Works by detecting the changes in blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain
When an area is more active it consumes more oxygen (haemodynamic response)
Produces 3-dimensional images (activation maps)
EEG - electroencephalogram
Measures electrical activity within the brain via electrodes that are fixed to an individual’s scalp using a skull cap
The scan recording represents the brainwave patterns that are generated from the action of millions of neurons
May indicate neurological abnormalities such as epilepsy, tumours or sleep disorders
ERPs - event-related potentials
All extraneous brain activity from the original EEG recording is filtered out leaving only those responses that relate to the presentation of a specific stimulus or performance of a specific task
What remains are event-related potentials. These are types of brainwave that are triggered by particular events
Post-Mortem Examinations
The analysis of a person’s brain following their death
May involve comparison with neurotypical brain in order to ascertain the extent of the difference
fMRI (STRENGTH)
Does not use radiation
Non-invasive
Risk free
Produces images with high spatial resolution
fMRI (WEAKNESS)
Can only capture a clear image of the person stays perfectly still
Poor temporal resolution due to a 5 second time lag
Can only measure blood flow in the brain and cannot home in on the activity of individual neurons
EEG (STRENGTH)
Contributed to understanding of sleep stages
High temporal resolution
EEG (WEAKNESS)
EEG signal is not useful for pinpointing the exact source of neural activity and does not allow researchers to distinguish between activities originating in different but adjacent locations
ERPs (STRENGTH)
Excellent temporal resolution
Has widespread use in the measurement of cognitive functions and deficits
ERPs (WEAKNESS)
Lack of standardisation in ERP methodology
Background noise and extraneous material must be completely eliminated to establish pure data
Post-Mortem (STRENGTH)
Vital in providing a foundation for early understanding of key processes in the brain
Wernicke and Broca relied on post-mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became a possibility
Improve medical knowledge and help generate hypothesis for further study
Post-Mortem (WEAKNESS)
Causation is an issue
Observed damage to the brain may not be linked to the deficits under review, but to some other unrelated trauma or decay
Post-mortem studies raise ethical issues of consent from the patient before death. Patients may not be able to provide informed consent
