Outline and evaluate electroencephalograms (EEGs) as a way of studying the brain.

Question 1

outline

Answer 1

EEGs measure general electrical activity in the brain using electrodes (which are fixed to the skull).

The scan records and plots brain wave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.

Unusual, arrhythmic patterns may indicate neurological abnormalities.

For example, brain scans of participants with brain tumours or brain injury show overall slowing of electrical activity, whilst epileptic patients show spikes of electrical activity.

Question 2

strength

Answer 2

A strength of using EEG’s is that they have excellent temporal resolution, which refers to its ability to precisely measure brain activity as it occurs. For example, unlike fMRI, an EEG can detect brain activity within 1 millisecond of it occurring.

Question 3

strength 2

Answer 3

Moreover, EEG’s have proven invaluable in the diagnosis of conditions such as epilepsy – a disorder characterised by random bursts of activity in the brain.

For example, EEG’s clearly present the random busts of activity on screen, so the ability to diagnose such conditions is made easier.

Question 4

limit

Answer 4

A limitation of using EEG’s is that they have poor spatial resolution, which refers to its ability to accurately localise function.

This is because the generalised picture provided by thousands of neurons means the exact source of the activity can be difficult to localise.

Moreover, it is difficult to isolate activity from one area from the activity in the adjacent area, making specific responses to a single stimulus impossible to identify.