How does functional MRI work?

Functional MRI (fMRI) measures changes in blood flow to show brain activity.

Functional MRI (fMRI) is a non-invasive imaging technique that uses magnetic fields to measure changes in blood flow in the brain. When a particular area of the brain becomes active, it requires more oxygen and glucose, which causes an increase in blood flow to that area. This increase in blood flow can be detected by fMRI, allowing researchers to see which parts of the brain are active during different tasks.

To perform an fMRI scan, the patient lies down in a large, cylindrical machine called a scanner. The scanner uses a strong magnetic field and radio waves to create detailed images of the brain. During the scan, the patient may be asked to perform various tasks, such as looking at pictures or solving problems, to activate different parts of the brain.

The fMRI scanner detects changes in blood flow by measuring the level of oxygen in the blood. Oxygen-rich blood has different magnetic properties than oxygen-poor blood, and the scanner can distinguish between the two. By comparing the levels of oxygen-rich blood in different parts of the brain, fMRI can create a map of brain activity.

Functional MRI has many applications in neuroscience and psychology, including studying brain function in healthy individuals and patients with neurological disorders. However, it is important to note that fMRI only measures changes in blood flow, not actual neural activity. Therefore, it is often used in conjunction with other techniques, such as EEG, to provide a more complete picture of brain function.