Functional MRI, or fMRI, is a type of brain imaging technique that measures and maps brain activity. It works by detecting changes in blood flow to different parts of the brain, which indicates areas that are more active during specific tasks or thoughts. When a brain region is active, it requires more oxygen, leading to increased blood flow in that area. This technology is widely used in both research and clinical settings to study brain functions, understand neurological disorders, and plan surgeries. fMRI provides valuable insights into how the brain processes information, making it an essential tool in neuroscience and psychology.