Ways of investigating the brain Flashcards
1
Q
What is an Function Magnetic Resonance Imaging (fMRI)?
A
- uses large magnets to detect the oxygenated blood
- produces 3D images showing which part of the brain is active
- works by detecting changes in blood oxygenation and flow occurring
- more active an area is , more oxygen is used
- to meet the demand blood flow is directed to the active area (haemodynamic response)
2
Q
What does an fMRI aid our understanding of?
A
localisation of function
3
Q
What are the strengths of fMRI’s?
A
- risk free
- non-invasive
- easy to use
- images have high spatial resolution (depicts detail by the mm)
provides clear image of brain localisation - doesn’t use radiation
4
Q
What are the weaknesses of fMRI’s?
A
- expensive compared to others
- patients have to be completely still
- poor temporal resolution
- there’s a 5 second lag time between image taken and the firing of a neuron
- only measures blood flow in the brain
- not individual neurons which means its difficult to tell what kind of brain activity is being represented
5
Q
What is an electroencephalogram (EEG)?
A
- measures electrical activity in the brain using electrodes that are on the scalp
- scan recordings shows brainwave patterns from actions of millions of neurons
- provides an overall account of brain activity
- used to diagnose neurological abnormalities ( epilepsy , tumours , sleep disorders etc)
- this is due to unusual arrhythmic patterns of activity
6
Q
What are the strengths of an EEG?
A
- good for diagnosing disorders (epilepsy)
- which involves random bursts of activity that can be easily detected
- contributed to our understanding of the stages of sleep
- very high temporal resolution
- can accurately detect brain activity at a resolution of a millisecond
7
Q
What are the weaknesses of an EEG?
A
- information received is generalised as it relates to thousands of neurons so we cannot say which neuron
- doesn’t allow researcher’s to distinguish between activities originating in different but adjacent locations
8
Q
What are Event-related Potentials (ERP’s)?
A
- uses the same technique as an EEG but it records when there’s an activity in reaction to a stimulus
- stimulus is presented multiple times and provides data using statistical analysis
- what is left = ERP’s which is brainwaves triggered by particular events
- many types such as attention perception
9
Q
What are the strengths of an ERP?
A
- neural responses are measured a lot more than in an EEG due to excellent temporal resolution
- widespread use in the measurement of cognitive functions and deficits
- many types have been identified
- for eg. - P300 component is thought to be involved in the allocation of attentional resources and maintenance of the working memory
10
Q
What are the weaknesses of an ERP?
A
- lack of standardisation in ERP methodology makes it difficult to confirm findings
- background noise and extraneous material need to be eliminated which is not always possible
11
Q
What are post-mortem examinations?
A
- analysis of the brain after death
- those who have a rare disorder or experienced unusual deficits in mental processes or behaviour are likely to have a post-mortem examination
- damaged areas are examined to try and establish a likely cause and it can involve the comparison of a typical brain
12
Q
What are the strengths of post-mortem examinations?
A
- Broca and Wernicke both relied on post-mortem studies in establishing links between language , brain and behaviour before brain imaging which was key to our early understanding of how the brain works
- improves medical knowledge
- helps to generate hypothesis for future studies
13
Q
What are the weaknesses of post-mortem examinations?
A
- damage observed may not be linked to the disorder they are reviewing but linked to unrelated trauma or decay
- ethical issues of consent from patient before death
- patients may not be able to provide informed consent due a condition
