title: Mobilization of Medial and Lateral Frontal-Striatal Circuits in Cocaine Users and Controls: An Interleaved TMS/BOLD Functional Connectivity Study.
abstract: The integrity of frontal-striatal circuits is an area of great interest in substance dependence literature, particularly as the field begins to develop neural circuit-specific brain stimulation treatments for these individuals. Prior research indicates that frontal-striatal connectivity is disrupted in chronic cocaine users in a baseline (resting) state. It is unclear, however, if this is also true when these circuits are mobilized by an external source. In this study, we measured the functional and structural integrity of frontal-striatal circuitry involved in limbic arousal and executive control in 36 individuals-18 cocaine-dependent individuals with a history of failed quit attempts and 18 age-matched controls. This was achieved by applying a transcranial magnetic stimulation to the medial prefrontal cortex (Brodmann area 10) and the dorsolateral prefrontal cortex (lateral Brodmann 9) while participants rested in the MRI scanner (TMS/BOLD imaging). Relative to the controls, cocaine users had a lower ventral striatal BOLD response to MPFC stimulation. The dorsal striatal BOLD response to DLPFC stimulation however was not significantly different between the groups. Among controls, DLPFC stimulation led to a reciprocal attenuation of MPFC activity (BA 10), but this pattern did not exist in cocaine users. No relationship was found between regional diffusion metrics and functional activity. Considered together these data suggest that, when engaged, cocaine users can mobilize their executive control system similar to controls, but that the 'set point' for mobilizing their limbic arousal system has been elevated-an interpretation consistent with opponent process theories of addiction.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.|Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.|Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Colleen A
authors.initials: CA
authors.lastname: Hanlon
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Logan T
authors.initials: LT
authors.lastname: Dowdle
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Hunter
authors.initials: H
authors.lastname: Moss
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Melanie
authors.initials: M
authors.lastname: Canterberry
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.|Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.|Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA.|Ralph H. Johnson VA Medical Center, Charleston, SC, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: George
mesh_terms: D000328:Adult; D001931:Brain Mapping; D019970:Cocaine-Related Disorders / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D010100:Oxygen / Q000097:blood*; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation
chemical_list: D010100:Oxygen