Nature of functional links in valuation networks differentiates impulsive behaviors between abstinent heroin-dependent subjects and nondrug-using subjects

Abstract

Advanced neuroimaging studies have identified brain correlates of pathological impulsivity in a variety of neuropsychiatric disorders. However, whether and how these spatially separate and functionally integrated neural correlates collectively contribute to aberrant impulsive behaviors remains unclear. Building on recent progress in neuroeconomics towards determining a biological account of human behaviors, we employed resting-state functional MRI to characterize the nature of the links between these neural correlates and to investigate their impact on impulsivity. We demonstrated that through functional connectivity with the ventral medial prefrontal cortex, the δ-network (regions of the executive control system, such as the dorsolateral prefrontal cortex) and the β-network (regions of the reward system involved in the mesocorticolimbic pathway), jointly influence impulsivity measured by the Barratt Impulsiveness Scale scores. In control nondrug-using subjects, the functional link between the β- and δ-networks is balanced, and the δ-network competitively controls impulsivity. However, in abstinent heroin-dependent subjects, the link is imbalanced, with stronger β-network connectivity and weaker δ-network connectivity. The imbalanced link is associated with impulsivity, indicating that the β- and δ-networks may mutually reinforce each other in abstinent heroin-dependent subjects. These findings of an aberrant link between the β- and δ-networks in abstinent heroin-dependent subjects may shed light on the mechanism of aberrant behaviors of drug addiction and may serve as an endophenotype to mark individual subjects’ self-control capacity.

Resting-State Neuroimaging and Neuropsychological Findings in Opioid Use Disorder during Abstinence: A Review

“…In the MCL system, stronger rsFC between nucleus accumben and the ventral areas of medial (PFC), including rostral anterior cingulate cortex (CC) and medial orbitofrontal cortex (OFC) were observed, suggesting that connectivity within reward and motivation circuits may help the interpretation of altered incentive salience for drugs and drug-associated cue. Without considering the smoking habit, the finding of Zhai et al (2015) was consistent with that of Ma et al (2010), while Wang et al (2016), on the other hand, showed reduction in rsFC between MCL regions and subcortical and cortical areas. It was noted that the reported abstinence duration of the OUD subjects underwent MMT (daily dose: 52.0 ± 29.4 mg) in Wang (Wang et al, 2016) study was relatively longer than that of the OUD subjects in Ma (Ma et al, 2010), where the daily dose of MMT was not reported, and that of the OUD subjects in Zhai (Zhai et al, 2015), where the treatment program was not reported in the study.…”

“…Without considering the smoking habit, the finding of Zhai et al (2015) was consistent with that of Ma et al (2010), while Wang et al (2016), on the other hand, showed reduction in rsFC between MCL regions and subcortical and cortical areas. It was noted that the reported abstinence duration of the OUD subjects underwent MMT (daily dose: 52.0 ± 29.4 mg) in Wang (Wang et al, 2016) study was relatively longer than that of the OUD subjects in Ma (Ma et al, 2010), where the daily dose of MMT was not reported, and that of the OUD subjects in Zhai (Zhai et al, 2015), where the treatment program was not reported in the study. It is not known if these factors (i.e., abstinence length, methadone maintenance length and dosage, and treatment program) played a role in the inconsistency of the rsFC alternation.…”

“…Opiate abstinent abusers have been compared to an extensive neuropsychological battery to normal controls (Zhao et al, 2009; Xie et al, 2011; Gerra et al, 2014; Morie et al, 2014; Yan et al, 2014; Zhai et al, 2015; Hou et al, 2016), to patients undergoing treatment program, such as MMT (Darke et al, 2000; Mintzer and Stitzer, 2002; Mintzer et al, 2005; Passetti et al, 2008), and subjects with known mental disorder, such as anxiety and depression (Zhou et al, 2012). These studies yielded some consistent results.…”

Resting-state Abnormalities in Heroin-dependent Individuals

“…Therefore, they concluded that -and -networks are in imbalanced interaction in heroin-dependent individuals. In line with this finding, Zhai et al (2015), using the ventral medial PFC as region of interest, reported that the rsFCbetween the vmPFC and the -network's components including NAc, right medial OFC, caudate bilaterally and right PCC was higher in heroin-dependent group compared to control group. However, the rsFCbetween the vmPFC and the components of -network such as right IFG and IPL as well as the dorsal medial and dorsolateral PFC bilaterally was significantly lower in heroindependent individuals compared to controls.…”

“…A more recent study investigating the role of valuation networks, -and -, in impulsive behaviors reported that the BIS-11 total score as well as all subscales were found to be higher in heroin-dependent group compared to controls (Zhai et al, 2015).The BIS-11 total score and the Motor Impulsivity subscale were positively associated with the -network's connectivity but negatively correlated to -network's connectivity in heroin group.…”