2-Minute Neuroscience: Electroencephalography (EEG)

Summary

Electroencephalography (EEG) measures the brain’s electrical activity using electrodes, usually placed on the scalp. It primarily detects activity from populations of neurons in the cerebral cortex rather than individual neurons. The signals mostly reflect postsynaptic potentials and are strongest in the small areas around each electrode.

EEG represents brain activity as waves that vary in frequency, amplitude, and shape. It can record activity linked to a particular event, such as completing a task or receiving a stimulus, as well as spontaneous activity. Activity associated with an event is sometimes called an event-related potential.

Uses, strengths, and limitations

• Clinical uses: EEG is commonly used to diagnose epilepsy and characterize seizures, monitor sleep to help diagnose sleep disorders, and assess other kinds of brain dysfunction.
• Strengths: It is relatively low-cost and can measure changes in brain activity on a millisecond timescale.
• Limitations: Because EEG reflects activity from groups of neurons, it is difficult to pinpoint a signal’s precise location. It is also better suited to measuring cortical activity than activity in deeper brain structures.

Speakers and sources

• Speaker: An unnamed narrator.
• Source: 2-Minute Neuroscience: Electroencephalography (EEG), from Neuroscientifically Challenged.