Background: Functional neuroimaging studies suggest that chronic cocaine use is associated with frontal lobe abnormalities. Functional connectivity (FC) alterations of cocaine-dependent individuals (CD), however, are not yet clear. This is the first study to our knowledge that examines resting FC of anterior cingulate cortex (ACC) in CD. Because ACC is known to integrate inputs from different brain regions to regulate behavior, we hypothesized that CD will have connectivity abnormalities in ACC networks. In addition, we hypothesized that abnormalities would be associated with poor performance in delayed discounting and reversal learning tasks. Methods: Resting functional magnetic resonance imaging data were collected to look for FC differences between 27 CD (5 women, age: M = 39.73, SD = 6.14 years) and 24 control subjects (5 women, age: M = 39.76, SD = 7.09 years). Participants were assessed with delayed discounting and reversal learning tasks. With seed-based FC measures, we examined FC in CD and control subjects within five ACC connectivity networks with seeds in subgenual, caudal, dorsal, rostral, and perigenual ACC. Results: The CD showed increased FC within the perigenual ACC network in left middle frontal gyrus, ACC, and middle temporal gyrus when compared with control subjects. The FC abnormalities were significantly positively correlated with task performance in delayed discounting and reversal learning tasks in CD. Conclusions: The present study shows that participants with chronic cocaine-dependency have hyperconnectivity within an ACC network known to be involved in social processing and "mentalizing. " In addition, FC abnormalities found in CD were associated with difficulties with delay rewards and slower adaptive learning.
Bibliographical noteFunding Information:
This research was supported by the National Institute on Drug Abuse (P20DA024196) and the National Center for Research Resources (5P41RR008079) from the National Institutes of Health, the General Clinical Research Center (M01 RR00400), the Center for Magnetic Resonance Research (BTRR—P41 RR008079 and NCC Grant P30 NS057091 ), the Medical Investigation of Neurodevelopmental Disorders Institute (R21MH79262), the PharmacoNeuroImmunology Program at the University of Minnesota (NIDA/NIH T32 DA007097), and the Minnesota Supercomputing Institute. We would like to thank the subjects who participated in this study. The authors report no biomedical financial interests or potential conflicts of interest.
- Anterior cingulate
- delayed discount
- functional connectivity
- reversal learning