Recent rsFC studies have also suggested patterns of abnormal connectivity between these primary nodes of a “cognitive control network” in both heroin (Yuan et al., 2011; Ma et al., 2010) and cocaine addicted samples (Kelly et al., 2011). For example, reduced rsFC strength between the ACC and dlPFC has been noted in heroin addicts (Ma et al., 2010). Additionally, in a sample of chronic cocaine-using individuals (n=25), Kelly and coworkers (2011) observed significant reductions in rsFC within and between lateral PFC and parietal areas, where reduced interhemispheric connectivity between lateral PFC regions predicted a higher incidence of self-reported cognitive failures (Fig 1C). Yuan and coworkers (2011) observed a similar pattern in abstinent heroin users such that reduced rsFC between lateral PFC and parietal regions was accompanied by reductions in gray matter density in those same regions, with years of use predicting greater reductions across both measures. Reduced rsFC between nodes within this putative cognitive control network is consistent with the behavioral and task-based imaging findings referenced above as well as self-reported cognitive deficits in drug-addicted populations (Ersche et al., 2005; Gruber et al., 2007; Hester & Garavan, 2004; Kelly et al., 2011).
