Abnormal Brain Default-Mode Network Functional Connectivity in Drug Addicts

Background: The default mode network (DMN) is a set of brain regions that exhibit synchronized low frequency oscillations at resting-state, and is believed to be relevant to attention and self-monitoring. As the anterior cingulate cortex and hippocampus are impaired in drug addiction and meanwhile are parts of the DMN, the present study examined addiction-related alteration of functional connectivity of the DMN. Methodology: Resting-state functional magnetic resonance imaging data of chronic heroin users (14 males, age: 30.1+/-5.3 years, range from 22 to 39 years) and non-addicted controls (13 males, age: 29.8+/-7.2 years, range from 20 to 39 years) were investigated with independent component analysis to address their functional connectivity of the DMN. Principal Findings: Compared with controls, heroin users showed increased functional connectivity in right hippocampus and decreased functional connectivity in right dorsal anterior cingulate cortex and left caudate in the DMN. Conclusions: These findings suggest drug addicts' abnormal functional organization of the DMN, and are discussed as addiction-related abnormally increased memory processing but diminished cognitive control related to attention and self-monitoring, which may underlie the hypersensitivity toward drug related cues but weakened strength of cognitive control in the state of addiction.