慢性海洛因成瘾者行为抑制的BOLD-fMRI研究

The BOLD-fMRI study of behavior inhibition in chronic heroin addicts

目的采用事件相关(stop-signal任务)功能MRI(functional MRI,fMRI)方法探讨慢性海洛因依赖者冲动和行为抑制缺陷的神经基础。方法选取17例慢性海洛因成瘾者和17名健康对照者,首先进行头部结构MRI扫描,然后对海洛因成瘾者及健康对照者在执行stop-signal任务的同时进行fMRI扫描。采用专业的功能神经成像分析软件AFNI进行数据处理和统计分析。结果行为学结果显示海洛因组对停止信号发生反应的反应时间(SSRT)明显长于对照组。fMRI结果显示病例组和对照组在初级运动区、辅助运动区后部等运动执行区均没有显著差异,但在要求对行为进行对照时,病例组在右侧背外侧前额叶、右侧腹侧前额叶、扣带回前部等脑区的激活强度都显著弱于对照组被试,而在双侧纹状体和杏仁核,病例组的激活强于对照组。结论右侧前额叶是执行抑制功能的主要脑区,扣带回与错误监控等能力密切相关,杏仁核一直被视为是冲动性、情绪对照的关键结构。这些脑区构成冲动与对照的神经环路,慢性海洛因依赖者抑制功能损伤与这个环路的活动异常有关。

Objective To identify the neural mechanisms of impulsivity and the response inhibition deficits of the chroin heroin users using event-related functional MRI （stop-signal task）. Methods Seventeen individuals with heroin dependence and 17 healthy control subjects underwent fMRI scan while executing stop-signal task after anatomicM scanning in 3.0 T scanner. The AFNI package was used for fMRI data preprocessing and statistical analysis. Results The behavioral data showed that the stop signal reaction rime （SSRT） of heroin users was significantly longer than that of the control group. There was no significant difference in activation of the primary motor cortex and supplementary motor area between two groups. Comparing to the control group, heroin users had weaker activation in the right dorsal lateral prefrontal cortex, right inferior prefrontal cortex, and anterior cingulated cortex, but stronger activation in b/lateral str/atum and amygdala while behavioral inhibition needed. Conclus/on The results suggest that heroin users have significant changes within impulsivity and inhibitory network, where the right prefrontal cortex is considered as main region for inhibition, while the anterior cingnlated cortex is associated with error monitoring, and the amygdale controls impulsivity and emotion.