Functional connectivity is a way of measuring the functional relationships between different sets of brain regions. In neurology, it is used to describe how different regions of the brain interact with each other to produce the complex neurological and behavioral expressions of cognition. Functional connectivity is measured through fMRI data, which is based on changes in the level of oxygenated blood flowing to different regions of the brain over time. By mapping these changes in activity levels, it is possible to detect patterns, or networks, of communication among brain regions. This approach provides an understanding of how structures and pathways in the brain are organized and used for certain processes. Functional connectivity has been used to study a wide range of neurological processes, such as attention, learning, memory, decision making, and creativity. It is also used as a tool to explore the underlying neural mechanisms of emotional processing and psychiatric disorders. In addition, it provides an essential view into the functional architecture of the brain, and how different regions across the brain collaborate to express behaviours. Overall, functional connectivity provides a way of studying the brain from an interdisciplinary perspective, bridging neuroscience, psychology, and psychiatry. By understanding how the brain networks are organized and interact with each other, it is possible to gain insight into how the brain enables and supports mental functioning, and to identify biomarkers associated with neurological and psychiatric disorders.