Studying the brain Flashcards
What are the four main ways to study brain activity?
- fMRI.
- EEG.
- ERP.
- Post-mortem.
What does fMRI stand for?
Functional magnetic resonance imaging.
How does an fMRI work?
It detects changes in blood oxygenation and flow that occur in response to neural activity. (when a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area.)
How does an fMRI show you which areas of the brain are active?
The most active areas require the most oxygen and therefore an increased oxygen supply is shown in the diagram.
What is the final product of an fMRI?
It produces a picture of the brain with certain areas of varying intensities of colour to show how much each area is being used.
What would an fMRI show during speech production?
Broca’s area would light up.
What would an fMRI show during speech comprehension?
Wernicke’s area would light up.
What is spatial resolution?
The capacity of the brain scan to tell you which areas of the brain are active.
What is temporal resolution?
The brains ability to tell you exactly when the activation occurred.
What are the two types of resolution?
Spatial and Temporal.
How long after an event does an fMRI show activity?
Approximately 1-4 seconds (low temporal resolution).
How accurate are fMRI scans?
Approximately 1-2mm (good spatial resolution).
(AO3) fMRI - Causation:
fMRI scans do not provide a direct measure of neural activity, they simply measure changes in blood flow and therefore you cannot infer causation (at a neural level).
(AO3) fMRI - Non-invasive:
fMRI is a non-invasive procedure, it does not use radiation or insertion of instruments into the brain, therefore virtually risk-free.
(AO3) fMRI - Spatial resolution:
fMRI scans have a good spatial resolution, approximately 1-2mm which is greater than other techniques. Therefore you can measure with a greater accuracy.
(AO3) fMRI - Temporal resolution:
fMRI has a low temporal resolution, the delay is around 1-4 seconds which is much worse than other techniques. Consequently, the ecological validity is decreased.
What is the premise behind fMRIs?
The idea that neurons in the brain are most active during a task use the most energy, therefore the most oxygen.
When haemoglobin dissociates from oxygen it changes its magnetic quality, how is this used during an fMRI?
Areas using more oxygen have a higher magnetic quality and show up a varying colour in the image.
(AO3) fMRI - Cost:
fMRI is very expensive, amongst the costliest techniques, a machine costs upwards of a million pounds.
(AO3) fMRI - Boredom
If the participant gets bored and moves or does not participate fully in the study then the results would be inaccurate.
What does EEG stand for?
Electroencephalography.
What is the premise that EEG technology is based on?
The idea that information is processed in the brain as electrical activity in the form of action potentials or nerve impulses, transmitted along neurons.
What is the cost of EEG technology?
EEG is relatively cheap compared to other scans such as fMRI, costing hundreds of thousands rather than millions.
What is the temporal resolution of EEG?
Almost spontaneous (a matter of milliseconds).
How is brain activity recorded with an EEG?
Electrical activity is recorded through electrodes attached to the scalp using a skull cap.
Which scanning technique is used in hospitals to diagnose sleeping disorders and epilepsy?
EEG, (electroencephalography).