What type of brain imaging can show functional activity by measuring blood flow and oxygenation?

• A. PET
• B. EEG
• C. fMRI
• D. CT scan

Answer: (C)

Functional imaging that reflects neural activity through changes in blood flow and oxygen use is captured by functional MRI. When a brain area becomes active, it requires more blood, and the local balance of oxygenated versus deoxygenated hemoglobin shifts in a way that MRI can detect. This Blood Oxygenation Level-Dependent, or BOLD, signal provides a map of which regions are engaged during a task, with good spatial resolution and without radiation exposure.

PET also measures brain function by tracking metabolic activity with radioactive tracers, which tells you where energy use is high, but it doesn’t directly measure blood flow and oxygenation and it involves radioactivity. EEG records the brain’s electrical activity and has excellent timing, but its spatial localization isn’t as precise and it doesn’t measure blood flow or oxygenation. CT scans show anatomy, not function.

So, the type of brain imaging that shows functional activity by measuring blood flow and oxygenation is functional MRI.