The Brain Practice Test

CT scan—uses X-rays to show structural differences; it is not designed to track task-related blood-oxygen changes over seconds.

fMRI—uses the BOLD signal to track blood oxygenation changes associated with neural activity; useful for functional task-based mapping.

MRI with contrast—primarily structural imaging; contrast can highlight anatomy or lesions but is not the standard measure of task activity via BOLD.

EEG—records scalp electrical activity with high temporal resolution; it does not directly measure blood oxygenation changes in specific deep regions.