OBJECTIVE: This study aimed to explore the functional connectivity of the default mode network (DMN) in crack-cocaine users, in comparison with that observed in age-matched non-drug-using controls. MATERIALS AND METHODS: Inpatient crack-cocaine users who had been abstinent for at least four weeks and age-matched non-drugusing controls underwent resting state functional magnetic resonance imaging. Images were acquired while the subjects rested with their eyes closed. After data preprocessing, DMNs were defined by spatial independent component analysis and seed-based correlation analysis, by chosen regions of interest centered in the ventral anterior cingulate cortex and in the posterior cingulate cortex. RESULTS: The functional connectivity of the DMN determined by independent component analysis did not differ between the crackcocaine users and the controls. However, the seed-based correlation analysis seeking a single metric of functional connectivity between specific brain regions showed that the negative connectivity between the ventral anterior cingulate cortex and the left superior parietal lobule was significantly greater in the crack-cocaine users than in the controls. CONCLUSION: The results suggest that selective extrinsic network connectivity of the DMN related to motor and executive function is impaired during crack-cocaine addiction.

Keywords: Substance-related disorders; Magnetic resonance imaging/methods; Brain/physiopathology; Image interpretation, computer-assisted; Functional neuroimaging.