甲基苯丙胺依赖者注意偏向的脑功能机制及转归

Attentional bias, which was defined as automatically increased priority in the attentional processing of substance-related stimuli, plays a key role in addiction development. Anterior cingulate cortex (ACC), and amygdala (Amyg) have been found to be associated with stimulus signals-related selection and control in attention processing. Imaging studies have found structure abnormalities in ACC and Amyg among substance abuse individuals. Available studies are not valid enough to explain the brain mechanism underlying this clinical feature and the tendency. Based on our previous neuroelectrophysiologic study among methamphetamine (MA) dependent individuals, we found MA-dependent individuals show attentional bias for MA-related cues which abnormal amplitudes of event-related potential (P300) will recover to normal level after abstinence. hus, the study hypotheses that attentional bias for MA-related cues was correlated with hyperactivity in ACC and hypoactivity in Amyg among MA-dependent individuals, while abnormal attentional bias-related activity might retune to the normal level after abstinence. This study intends to establish a health-controlled longitudinal follow-up study cohort. By using functional magnetic resonance scanning (fMRI), abnormal activated brain regions will be located during a MA Addiction Stroop color-matching task using MA-related and neutral words. This study will firstly investigate the characteristics of attentional bias-related brain activity (particularly in ACC and Amyg), and secondly investigate the changes of attentional bias-related brain activity within 12 months of abstinence. This study will provide novel evidence to better understanding the neurobiological mechanism of MA dependence.

注意偏向，即对毒品相关线索的注意加工自动增强，对成瘾发展起关键作用。前扣带回（ACC）和杏仁核（Amyg）在正常人注意加工过程中起重要调控作用。物质依赖者存在上述结构损害，但其注意偏向相关脑功能特征和戒断期转归尚不明确。我们前期针对甲基苯丙胺（Methamphetamine，MA）依赖者的脑电生理研究发现：MA依赖者对毒品相关线索存在注意偏向，事件相关电位（P300）波幅异常随着保持戒断逐渐恢复。因此，本研究假设MA依赖者毒品相关线索注意偏向与ACC激活增强、Amyg激活减弱有关，其激活异常将随着持续戒断逐渐恢复至正常水平。本研究拟采用前瞻性队列研究设计，以“MA成瘾Stroop任务”研究注意偏向，通过功能磁共振技术，首先明确MA依赖者注意相关脑区（ACC、Amyg）功能的改变特征，其次通过随访明确戒断后一年内相关脑区功能异常的转归。本研究将对深化认识MA依赖的神经生物学机制提供理论线索。

注意偏向，即对毒品相关线索的注意加工自动增强，对成瘾发展起关键作用。前扣带回（ACC）和杏仁核（Amyg）在正常人注意加工过程中起重要调控作用。物质依赖者存在上述结构损害，但其注意偏向相关脑功能特征和戒断期转归尚不明确。我们前期针对甲基苯丙胺（Methamphetamine，MA）依赖者的脑电生理研究发现：MA依赖者对毒品相关线索存在注意偏向，事件相关电位（P300）波幅异常随着保持戒断逐渐恢复。本研究以MA依赖者为研究对象，采用前瞻性队列研究设计，以“MA成瘾Stroop任务”和功能磁共振技术研究注意偏向。通过与健康对照者比较，结果显示：在面对毒品相关线索时，MA依赖者的执行控制网络和默认网络激活异常，执行控制网络的额上回和角回、默认网络的楔前叶和颞中回可能是MA依赖者注意偏向、线索诱发后渴求和线索反应性共同的神经生物学基础。对MA依赖者随访6个月，与基线比较显示，上述MA依赖者对毒品相关线索注意偏向的影像学指标未发生改变，提示基于执行控制网络和默认网络激活异常的毒品相关线索注意偏向并未在6个月内恢复。然而，以DLPFC为靶点的重复经颅磁刺激干预有降低MA依赖者对毒品相关线索的注意偏向，其机制包括rTMS使得前额叶与其他脑区之间的功能连接增强有关。本研究结果对深化认识MA依赖的神经生物学机制提供理论线索。