What does functional connectivity measure in the brain?

Functional connectivity specifically measures the correlation or interaction between different brain regions when they are not necessarily performing a particular task, often referred to as resting state connectivity. This type of measurement looks at how different areas of the brain communicate with each other by examining the spatial correlations of their activity patterns.

While the option that highlights connectivity during tasks (which suggests dynamically assessing how various brain networks operate together while engaged in activities) does touch on important aspects of brain function, functional connectivity primarily emphasizes the inherent relationships that exist between brain regions, particularly in a resting state. Task-related connectivity often falls under the broader investigation of network dynamics during specific cognitive processes rather than the steady-state functional linkages assessed when the brain is at rest.

This concept contrasts with other ideas mentioned in the choices, such as connection strength or overall brain coherence, which might refer to different aspects of brain activity or organization. Focusing on the inherent correlations during rest provides a foundation for understanding how brain networks function and interact, irrespective of external tasks.