Ways of Investigating The Brain Flashcards
What is fMRI?
Functional Magnetic Resource Imaging. Works by detecting changes in blood oxygenation and flow that occur as a result of brain activity in specific parts of the brain. When an area is more active it consumes more oxygen to meet this demand.
What is EEG?
Electroencephalograms measure electrical activity within the brain via electrodes that are fixed to an individuals scalp using a scull cap. This represents the brainwave patters.
What are ERPs?
Event-Related Potentials are a statistical averaging technique which filters out extraneous brain activity - leaving only the responses that relate to a specific tasks. What remains are event-related potentials - brainwaves triggers by particular stimuli.
What are Post-Mortem Examinations?
Analysing a persons brain after their death, usually those with a rare disorder or have experienced unusual deficits in mental processes or behaviour during their lifetime. Areas of damage are examined as a means of establishing the likely cause of affliction.
What is the strength for fMRIs?
It does not rely on the use of radiation, so is essentially risk-free, non invasive and straightforward to use. Produces images with very high spatial resolution to the millimetre, providing a clear picture of how brain activity is localised.
What is the weakness for fMRIs?
Very expensive and can only capture a clear image if the person stays still. Also has poor temporal resolution because there is a 5-second delay between on-screen representation and neural firing. It can also only detect blood flow, but not home in on individual neurons.
What is the strength for EEGs?
Proved invaluable in the diagnosis of epilepsy, a disorder characterised by random bursts of activity in the brain that can be easily detected on screen. It has contributed much to our understanding of the stages involved in sleep - very temporally reliable.
What is the weakness for EEGs?
The generalised nature of the information we get from it. It represents the total firing of millions of neurons, and cannot pinpoint the exact source of neural activity and doesn’t allow researchers to distinguish between activities in different locations.
What is the strength for ERPs?
They address the issues with EEGs - taking out the unnecessary data and only showing that which relates to the event measured. They have excellent temporal resolution, which has led to their widespread use in the measurement of cognitive functions and deficits.
What is the limitation for ERPs?
Critics have pointed out a lack of standardisation in ERP methodology between different studies making it difficult to confirm findings. It also doesn’t always filter out 100% of extraneous data, so there may be some confounding data remaining.
What is the strength of Post-Mortem Examinations?
It was vital in proving a foundation for initial understanding of key processes. Broca and Wernicke relied heavily on this to establish links between language, brain and behaviour long before neuroimaging.
What is the limitation of Post-Mortem Examinations?
Causation is an issue. Observed damage may be unrelated to the issue being investigated. A further issue is that there is no consent from the patient before death, and they may not be able to provide informed consent - HM.
