A recent study found the severity of nicotine addiction was negatively correlated with the strength of connectivity between dorsal ACC and striatal circuits (Hong et al., 2009). However, in the present study, in contrast to controls, we found the connectivity between ventral ACC and NAc was stronger in heroin user who reported higher (p < 0.001) Fagerström Test for Nicotine Dependence (FTND) scores, and there was no significant between-group difference on the connectivity between dorsal ACC and NAc. Thus, we proposed that the effect of nicotine addiction severity may not be a main effect of alteration on functional connectivity found in our study. Nonetheless, as our two groups were not well controlled for nicotine addiction severity, this question should be addressed in future studies.
