Glossary · Research and quantitative methods
Functional magnetic resonance imaging (fMRI)
A specialized MRI method that estimates changes associated with brain activity through time-varying blood-flow or blood-oxygenation signals.
Also called: fMRI, functional MRI
Definition
Functional magnetic resonance imaging repeatedly measures MRI signal changes while a person rests or performs a task. Common analyses use blood-oxygen-level-dependent contrast as an indirect measure associated with neural activity and compare those measurements across time, conditions, or regions.
Why it matters
fMRI combines medical imaging, experimental design, time-series processing, statistics, spatial analysis, and cautious interpretation.
Common misunderstanding
An fMRI activation map is not a direct photograph of thoughts or neurons firing, and its interpretation depends on the acquisition, model, thresholding, controls, and study design.
Related terms
Related system family: Measurement & Search Signals
Sources
- Magnetic Resonance Imaging (MRI) (opens in a new tab) · National Institute of Biomedical Imaging and Bioengineering
Last reviewed July 16, 2026