Ways of studying brain (scans) Flashcards
What are the four techniques?
- Functional magnetic resonance imaging (fMRI)
- Electroencephalogram (EEG)
- Event- related potentials (ERPs)
- Post- mortem examinations
What is an fMRI?
A method used to measure brain activity while a person is performing a task. fMRI detects radio waves from changing magnetic fields. This enables researchers to detect which regions of the brain are rich in oxygen and thus active. Produces 3D images showing the part of brain involved in mental processes.
What is an EEG?
A record of the tiny electrical impulses produced by the brains activity. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.It uses a skull cap, and can indicate neurological abnormalities such as epilepsy.
What is an ERP?
The electro physical response of the brain to a specific sensory, cognitive or motor event can be isolated through statistical analysis of EEG data. ERPs are a separate brainwave triggered by particular events.
What is a PME?
The brain is analysed after death to determine whether certain observed behaviours during the persons lifetime can be linked to structural abnormalities in the brain. Can compare to neurotypical to assess difference.
Evaluation of fMRI?
Strength- doesn’t rely on the use of radiation it is risk free non invasive and straight forward. High spatial resolution, clear safe picture
Weakness- expensive and has poor temporal resolution because there’s a 5 second time lag between image and firing of neuronal activity. Doesn’t present moment to moment activity.
Evaluation of EEG?
Strength- useful in studying states of sleep, high temporal resolution ( a single millisecond) RW usefulness
Weakness- generalised nature, not useful for pinpointing exact source of neural activity not allowing researchers to distinguish between activities originating in different but adjacent locations
Evaluation of ERP?
Strength- bring more specificity then raw EEG data, also have excellent temporal resolution compared to fMRI. Used to look at working memory
Limitation- critics have pinpointed lack of standardisations in ERP, difficult to confirm findings. To establish pure data extraneous material must be completed eliminated
Evaluation of PME?
Strength- PME is vital in foundation of key processes in brain (Wernicke and Broca) relied on these before neuroimaging. HMs case was identified by PME
Limitations- causation observed deficits may be unrelated trauma or decay. Ethical issues, may not be able t provide informed consent such as HM unable to form memories or provide consent.
