2) Biopsychology - Ways of Scanning the Brain Flashcards
What does fMRI stand for?
Functional Magnetic Resonance Imaging
How does fMRI work?
- Detects changes in blood oxygen and flow which occur due to neural activity.
- When an area of the brain is more active, it consumes more oxygen so in response more oxygen is directed to the part which is active.
How does fMRI assist in our understanding of localisation of function?
Produces a 3D image showing which parts are involved.
What do EEG’s do?
- Measure neuron activity by detecting electrical activity using electrodes fixed on the scalp of the individual by using a skull cap.
How do EEG’s show activity?
Show brainwave patterns which provide an overall account of brain activity.
What does ERP stand for?
Event-Related Potentials
What are ERPs?
- The isolation of results from EEGs since EEGs give a general measure of brain activity.
- They leave behind specific types of brainwaves (ERP) which are triggered by specific events.
What are post-mortem examinations?
- Involves the analysis of a person’s brain after death.
- Likely to have a rare disorder or problem.
- Allows the establishment of the cause of affliction the person experienced.
- May involve the comparison of a neurotypical brain.
Evaluate fMRIs
+ Safe, does not use radiation
+ Straightforward to use
+High spatial resolution
- Expensive
- Person has to stay still for a clear image
- Poor temporal resolution; 5s lag
- Cannot determine the exact kind of brain activity as it only measures blood oxygen levels not the individual neurone activity.
Evaluate EEGs
+ Invaluable in the diagnosis of conditions such as epilepsy which show random bursts of activity in the brain.
+ Allowed the discovery and understanding of the stages in sleep through ultradian rhythms.
+ High temporal resolution.
- Cannot pinpoint the exact source of neural activity.
- ## Researchers cannot distinguish between activities originating in different but adjacent locations.
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Evaluate ERPs
+ More specific than EEGs.
+ High temporal resolution
- Background noise and extraneous material must be eliminated which is not always easy to achieve.
- Lack of standardisation methodology between studies which make it difficult to confirm findings.
Evaluate Post-Mortems
+ Vital in providing the foundation of understanding the brain’s key processes.
Shown by Broca and Wernicke.
- Causation is not exact, could be due to trauma or decay not deficits.
- Ethical issue of informed consent. People who are examined have conditions which could have affected their way of thinking, such as HM who couldn’t form memories but still consented to the examination.
