Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique that allows researchers to measure and map brain activity by detecting changes in blood flow and oxygen levels in the brain. It is often used to study how different areas of the brain are involved in certain cognitive functions and behaviors, such as memory, attention, decision-making, and emotions. fMRI is widely used in neuroscience research, clinical settings, and psychology to better understand the brain and its functions.