PFC, which is believed to be responsible for restraining craving and cognitive control, was found to be impaired in drug abuse or relapse (Goldstein et al., 2004; Yang et al., 2009). Dorsal ACC is in responsible for inhibition controlling and conflict monitoring (Bush et al., 2000). Resting-state functional connectivity was found between these regions in a previous study (Margulies et al., 2007), implicating the dorsal–caudal ACC-based frontoparietal attention networks. In the present study, heroin users showed reduced functional connectivity within the circuit of cognitive control (between dorsal ACC and PFC) and between the circuits of cognitive control and motivation (between PFC and OFC, between dorsal ACC and ventral/rostral ACC). These observations, which are consistent with the results of a recent diffusion tensor imaging study reporting reduced white matter integrity in heroin users in the frontal and cingulate areas (Liu et al., 2008), suggested diminished cognitive control function and weakened cognitive control upon craving and motivation in heroin users. Taken together, the abnormality of functional connectivity in heroin users observed here supports the theories of addiction positing that the drug craving
