What is the purpose of EEG in research?

• A. To measure brain activity through electrodes placed on the scalp.
• B. To measure blood flow in the brain.
• C. To image brain structure with high resolution.
• D. To measure muscle activity only.

Answer: (A)

EEG is used to capture the brain’s electrical activity by placing electrodes on the scalp, picking up the rapid voltage changes generated by neural populations. This setup gives researchers millisecond-level timing, so we can see how the brain responds to a stimulus or task in real time and study patterns of neural oscillations and event-related responses. It’s a noninvasive, relatively accessible method that directly reflects neuronal electrical activity.

Because it measures electrical signals, EEG provides excellent temporal resolution but relatively coarse spatial localization compared to imaging methods that track blood flow or brain structure. Other approaches that assess blood flow (like fMRI) or image anatomy (like MRI) or measure muscle activity (like EMG) address different aspects of physiology, not the precise electrical dynamics of brain function that EEG captures.