What type of imaging technique is primarily used to measure brain metabolic activity using blood flow?

Functional MRI (fMRI) is the primary imaging technique used to measure brain metabolic activity through blood flow. This method takes advantage of the fact that neural activity in the brain requires energy, which is supplied by increased blood flow to active areas. fMRI detects changes in blood oxygenation levels, providing insights into which regions of the brain are more active during specific tasks.

When neurons become active, they consume oxygen, leading to a subsequent increase in blood flow to replenish the oxygen supply. fMRI captures this hemodynamic response, allowing researchers to map brain activity with high spatial resolution. This technique has become invaluable in cognitive neuroscience, enabling the study of brain functions related to decision-making, emotions, memory, and other cognitive processes.

In contrast, while Magnetic Resonance Imaging (MRI) provides detailed anatomical images of the brain's structure, it does not measure metabolic activity. Computed Tomography (CT) is primarily used for imaging bone structures and detecting bleeding or swelling, rather than measuring dynamic physiological processes. Near-Infrared Spectroscopy (NIRS) is a less common technique that measures cerebral blood flow but does so using light rather than magnetic fields; it is often used in specialized settings for continuous monitoring rather than general brain mapping. Thus, f