By Jason Hreha

Glossary

Functional magnetic resonance imaging

Reviewed by Jason Hreha

Published 1 min read

What is Functional Magnetic Resonance Imaging?

Functional magnetic resonance imaging (fMRI) uses changes in magnetic-resonance signals to study brain function. Common BOLD methods measure blood-oxygenation changes associated with neural activity, rather than recording neurons directly.

How it works

fMRI can measure activity-related changes at a spatial scale of millimeters. Its timing is slower than the underlying neural activity: the hemodynamic response commonly peaks several seconds later. It is widely used to study brain function. fMRI has revealed the neural correlates of decision-making, emotion, memory, language, and social cognition.

Limitations include

  • susceptibility to motion artifacts,
  • the inability to distinguish excitatory from inhibitory activity,
  • and the indirect relationship between the blood signal and actual neural processing.

Applied example

In a study of the ultimatum game, Sanfey and colleagues (2003) found stronger anterior insula activity for rejected unfair offers. This is an association between an imaging signal and a decision. The imaging result alone does not identify which emotion, if any, caused the decision.

Why it matters

fMRI lets researchers compare where activity-related signals change under different task conditions. That is useful evidence about brain function. Turning the pattern into an explanation still requires more than naming the region that lights up.

Sources and further reading

Raichle (1998) reviews the physiological basis of functional brain imaging.