WAYS OF STUDYING THE BRAIN Flashcards
fMRI
> Highlights active areas of the brain
Detects change in both blood oxygenation and flow that occur due to neural activity in specific brain areas
When a brain area is more active, it consumes more oxygen and blood flow is directed to the active area (haemodynamic response)
produces a 3D image showing which parts of the brain are active and must be involved in particular mental processes.
EEG
> Shows overall electrical activity
Measures electrical activity within the brain via electrodes using a skull cap
The scan recording represents the brainwave patterns generated from thousands of neurons, shows overall brain activity.
Often used as a diagnostic tool, for example. unusual arrhythmic patterns of brain activity may indicate abnormalities such as epilepsy, tumours or sleep disorders.
ERP’s
> brainwaves related to particular events
Event-related potentials are what is left when all extraneous brain activity from an EEG recording is filtered out.
done using statistical technique, leaving only the responses that relate to the presentation of a specific stimuli.
ERP’s are types of brainwave that are triggered by particular events
Research has revealed many different forms of ERP and how these are linked to cognitive processes (eg. perception and attention)
Post-Mortem Examination
> A technique involving the analysis of a person’s brain following their death
Areas of the brain are examined to establish the likely cause of a deficit or disorder that the person experienced in life.
This may also involve comparison with a neurotypical brain in order to assess the extent of the difference.
Evaluation Points fMRI
> Risk-free and high spatial resolution
>Expensive and poor temporal resolution
Evaluation points EEG
> Practical uses and high temporal resolution
>Information is generalised and source not pinpointed
Evaluation points ERP
> Specificity and good temporal resolution
>Lack of standardisation and background ‘noise’
Evaluation Points Post-Mortems
> Localisation and medical research
>Knowing causation and ethics
PEEL IT: fMRI, strengths
P- Strengths of fMRI are that it is risk free and high spatial resolution.
E-Unlike other scanning techniques (eg. PET), fMRI doesn’t rely on the use of radiation and is safe.
E-It also produces images with high spatial resolution, showing detail by the millimetre.
L-This means fMRI can safely provide a clear picture of how brain activity is localised.
PEEL IT: fMRI, limitations
P-Limitations of fMRI are that it is expensive and poor temporal resolution
E-fMRI is expensive compared to other techniques
E-It has poor temporal resolution because of 5-second lag between initial neural activity and image.
L-This means fMRI may not truly represent moment-to-moment brain activity.
PEEL IT: EEG, strengths
P- Strengths of EEG are practical uses and high temporal resolution.
E-EEG has contributed to our understanding of the stages of sleep
E-It has high temporal resolution - brain activity in one millisecond
L-This shows the real-world usefulness of the technique
PEEL IT: EEG, limitations
P-Limitations of EEG are information is generalised and source not pinpointed.
E-The EEG produces a generalised signal from thousands of neurons
E-It is difficult to know the exact source of neural activity.
L- Therefore EEG can’t distinguish the activity of different but adjacent neurons.
PEEL IT: ERP, strengths
P-Strengths of ERP are specificity and good temporal resolution.
E-Measures of neural processes more specific with ERP’s than EEGs.
E-ERP’s have excellent temporal resolution, better than fMRI.
L-This means that ERP’s are frequently used in cognitive research.
PEEL IT: ERP, limitations
P- Limitations of ERPs are lack of standardisation and background ‘noise’
E- Lack of standardisation makes it difficult to confirm findings in studies involving ERPs
E- Background ‘noise’ and extraneous material must be completely eliminated.
L- These issues are a problem because they may not always be easy to achieve
PEEL IT: Post-Mortems, Strengths
P- Strengths of post-mortems are in localisation and medical research.
E- Broca and Wernicke both relied on post-mortem studies.
E- Used to link HM’s memory deficits to damage in his brain.
L- This means they continue to provide useful information.
