Resting-state functional connectivity is assessed by the correlation of spontaneous fluctuations of blood oxygen level-dependent (BOLD) signals in different regions of the “resting” brain and is thought to provide a measure of its functional organization (Fox and Raichle, 2007). Studies have outlined a number of resting-state networks corresponding to critical brain functional organizations including movement, vision, audition, language, episodic memory, executive function, and salience detection (Fox and Raichle, 2007). During the acquisition of resting-state functional magnetic resonance imaging (fMRI) data, participants are asked to rest quietly instead of performing tasks, making it potentially more readily applicable than functional activation MRI in clinical settings. A number of groups have begun to study the resting state connectivity in a variety of neuropsychiatric disorders such as Alzheimer’s disease, depression, and schizophrenia (Greicius, 2008; Liu et al., 2007; Wang et al., 2007; Zhou et al., 2008).
