AO1 Ways of studying the brain: scanning techniques, including functional magnetic resonance imaging (fMRI); electroencephalogram (EEGs) and event-related potentials (ERPs); post-mortem examinations.

Functional magnetic resonance imaging (fMRI)

Technique for measuring changes in brain activity while a person performs a task. It measures changes in blood flow in particular areas of the brain which indicates increased neural activity in those areas.

Strengths of fMRI

It’s non-invasive as it doesn’t expose the individual to harmful radiation unlike CT scans and PET scans.

Compared to EEG it has better spatial resolution.

Weaknesses of fMRI

As it measures change in blood flow, it is not direct measure of neuronal activity in areas of the brain.

Overlooks the networked nature of brain activity as it focuses on localisation.

Electroencephalogram (EEG)

This measures electrical activity in the brain via electrodes that are fixed to an individual’s scalp either individually or using a skull cap

Strengths of EEG’s

Unlike fMRIs, they have high temporal resolution.

Useful in the diagnosis of conditions such as epilepsy

Weaknesses of EEG’s

Unlike fMRI’s cannot tell us about activity in deeper parts of the brain.

Main drawback lies in the generalised nature of the information received.

Event-related potential (ERP)

Very small voltage changes in the brain that are triggered by specific events ot stimuli.

Strengths of ERP’s

Can measure neural processes more accurately than using raw EEG data.

As they are derived from EEG measurements, they have excellent temporal resolution.

Weaknesses of ERPs

It may be difficult to eliminate background ‘noise’.

Can only study the cortex.

Post-mortem examinations (PME’s)

Involves the analysis of a person’s brain following their death. It’s often used in those who have a rare disorder or particular difficulties in mental processes or behaviour during their life. This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.

Strengths of PMEs

Allow for more detailed examinations of neuroanatomical and neurochemical aspects of the brain than what would be possible with the sole use of non-invasive techniques.

Weaknesses of PMEs

Causation is an issue with these investigations as the evidence is correlational.