Ways of investigating the brain Flashcards
What is an fMRI?
A functional magnetic resonance image detects changes in blood oxygenation and flow in the brain. When a brain area is more active, more oxygen is used and more blood is directed, showing which part of the brain is being used.
What are the strengths and weaknesses of fMRIs?
A strength is that it doesn’t rely on radiation and it is virtually risk free. It also produces images with a high resolution. However, it is expensive and the patient must lay perfectly still. It also has poor temporal resolution as there is a 5 second lag.
What is an EEG?
An electroencephalogram measure electrical activity within the brain via electrodes on a skull cap. The scan records brain waves that are generated from neurons. They can be used for diagnosing epilepsy, tumours or sleep disorders.
What are the strengths and weaknesses of EEGs?
They have provided diagnosis for epilepsy and disorders as well as providing evidence for sleep. It has a high temporal resolution and can detect activity at a resolution of a millisecond. However, it is difficult to pinpoint the exact source of neural activity.
What is an ERP?
Event related potentials filter out extraneous brain activity from an EEG, leaving only brainwaves which are triggered by particular events.
What are the strengths and weaknesses of ERPs?
ERPs are a more specific measure of neural processes and they have good temporal resolution. Researchers have also been able to identify different ERPs and describe the role of these in cognitive functioning. However, there is a lack of standardisation between studies and removing the extraneous information may be very difficult.
What are post-mortem examinations?
It is a technique carried out after death to look at people’s brains. This allows areas of damage to be found and to show how certain disorders could affect the brain.
What are the strengths and weaknesses of post mortems?
They are vital in showing key processes in the brain and for improving medical knowledge. However, causation may be an issue as observed damage may not be related to the issue under review. There are also ethical issues of informed consent.
