8.15—Medical imaging of the brain

Brain imaging methods answer different questions: structural scans show anatomy, while functional methods track activity or blood flow during a task. The interpretation depends on timing, resolution and the comparison condition.

A region that is more active during a task may be involved without being the only cause. Converging evidence from lesions, stimulation and behaviour strengthens a localisation claim.

If a motor task increases activity in a cortical area compared with a matched rest condition, the result supports involvement; it does not prove that the area alone controls movement.

Correlation between activity and a task is not proof of a single function, and an image is not a diagnosis without clinical context.