Which cognitive neuroscience method measures electrical activity of the brain with electrodes placed on the scalp?

• A. fMRI
• B. EEG
• C. PET
• D. DTI

Answer: (B)

Electrical activity recorded from the scalp with electrodes is what EEG does. It directly measures voltage fluctuations produced by synchronized neural firing, giving very fast, millisecond-level temporal precision and capturing real-time brain activity. That scalp-based electrical measurement is the key feature described. Other methods work differently: fMRI tracks changes in blood flow to infer activity, offering strong spatial resolution but no direct electrical measurement and with slower changes; PET images metabolic processes using radioactive tracers; DTI maps the diffusion of water to reveal white matter connections, not electrical signals. So EEG is the method that matches the description.