The negative BOLD responses in the rACC were higher and the CM signals in rACC were lower for cocaine abusers than for control subjects. The rACC, which is innervated by DA, noradrenergic [47] and serotonergic [48] neurons has been implicated in generation or regulation of spontaneous internal thoughts, emotions, anxiety and in internal conflict resolution [49]–[52]. Indeed, the rACC activates during emotional tasks and deactivates during cognitive tasks [53], [54]. Taking into account that compared to controls cocaine subjects showed rACC hypoactivation during this [16] and other [17], [18], [55] fMRI paradigms, the higher negative BOLD responses and the lower CM signals in rACC may reflect lower DA-mediated suppression of task-irrelevant emotional responses during fMRI in cocaine abusers.
