Neuroimaging Research Branch, National Institute on Drug Abuse-Intramural Research Program , Baltimore, MD , USA .
Am J Drug Alcohol Abuse. 2013 Nov;39(6):424-32. doi: 10.3109/00952990.2013.847446.
Dysregulated striatal functioning coupled with executive control deficits arising from abnormal frontal cortical function are considered key mechanisms in the development and maintenance of cocaine addiction. The same features are thought to underlie high trait impulsivity observed in cocaine-addicted populations.
Employing resting state functional connectivity, the current study sought to identify cortico-striatal circuit alterations in cocaine addiction and examine the degree to which circuit connectivity contributes to relapse risk and impulsivity among cocaine-addicted individuals.
Whole-brain resting-state functional magnetic resonance imaging connectivity was assessed in 45 cocaine-addicted individuals relative to 22 healthy controls using seed volumes in the left and right caudate, putamen and nucleus accumbens. Cocaine-addicted individuals completed scans in the final week of a 2-4 weeks residential treatment episode. Relapse by day 30 post-discharge served to separate cocaine-addicted individuals into relapse and non-relapse groups. All participants completed the Barratt Impulsivity Scale (BIS-11a).
Cocaine-addicted individuals exhibited reduced positive connectivity between the bilateral putamen and posterior insula and right postcentral gyrus. Group differences were primarily driven by reduced connectivity in relapse individuals relative to controls. No relapse versus non-relapse differences emerged. Impulsivity (BIS-11a) was higher in cocaine-addicted participants, an effect that was partially mediated by reduced putamen-posterior insula connectivity in this group.
Cocaine addiction, relapse risk and impulsivity were associated with reduced connectivity in putamen-posterior insula/postcentral gyrus circuits implicated in temporal discounting and habitual responding. Findings provide new insight into the neurobiological mechanisms underlying impulsivity and relapse in cocaine addiction.
纹状体功能失调与前额皮质功能异常导致的执行控制缺陷被认为是可卡因成瘾发展和维持的关键机制。同样的特征被认为是可卡因成瘾人群中观察到的高特质冲动的基础。
本研究采用静息态功能连接，旨在确定可卡因成瘾中的皮质-纹状体回路改变，并探讨回路连接对可卡因成瘾个体的复发风险和冲动性的影响程度。
使用左、右尾状核、壳核和伏隔核的种子容积，对 45 名可卡因成瘾者和 22 名健康对照者进行全脑静息态功能磁共振成像连接评估。可卡因成瘾者在 2-4 周住院治疗结束前完成扫描。出院后第 30 天的复吸情况将可卡因成瘾者分为复吸组和非复吸组。所有参与者都完成了巴瑞特冲动量表（BIS-11a）。
可卡因成瘾者双侧壳核与后岛叶和右侧中央后回之间的正连接减少。组间差异主要是由复吸者相对于对照组的连接减少引起的。没有出现复吸与非复吸的差异。可卡因成瘾者的冲动性（BIS-11a）较高，这一效应部分被该组壳核-后岛叶连接减少所介导。
可卡因成瘾、复发风险和冲动性与涉及时间折扣和习惯性反应的壳核-后岛叶/中央后回回路的连接减少有关。研究结果为可卡因成瘾中冲动性和复发的神经生物学机制提供了新的见解。
