Glossary
Functional connectivity
What is Functional Connectivity?
Functional connectivity describes statistical dependence between signals from separate brain regions. It is often estimated as a correlation, which does not by itself establish direct anatomical connections or causal influence.
How it works
In resting-state fMRI, researchers compare fluctuations in blood-oxygen-level-dependent signals while participants are not performing a specific task. The resulting patterns help characterize networks, but movement can create misleading correlations.
Applied example
A person lies quietly in a scanner. Signals from regions in the default mode network fluctuate together. Researchers can use that statistical relationship to characterize a network, even though the person is not doing a prescribed task.
Why it matters
Brain regions do not work in isolation. Functional connectivity lets researchers examine relationships among their signals. A correlated pattern is a starting point for explaining those relationships, not proof that one region directly drives another.
Power and colleagues (2012) show why head motion must be addressed before interpreting network correlations.