Department of Radiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States.
Neuropsychologia. 2017 Dec;107:102-107. doi: 10.1016/j.neuropsychologia.2017.11.003. Epub 2017 Nov 17.
Tobacco use disorder is frequently comorbid with emotional disorders, each exerting reciprocal influence on the other. As an important hub for emotional processing, amygdala may also play a critical role in tobacco addiction. Therefore, we aimed to investigate the volume and spontaneous activity of the amygdala in nicotine-dependent individuals and their relationships with cigarette use. A total of 84 smokers (aged 22-54 years) and 41 nonsmokers (aged 26-56 years) were enrolled in the present study. 3D-T1 weighted images and resting-state fMRI images were acquired from all participants. We used ROI-wise volume, fractional amplitude of low frequency fluctuation (fALFF) and resting-state functional connectivity (FC) to assess structural and functional changes of the amygdala in the smokers. There was no significant difference between smokers and nonsmokers on amygdala volume (p > 0.05). When compared to nonsmokers, increased fALFF in the right amygdala was observed in smokers (p = 0.024). In addition, increased FC between the left amygdala and the right precuneus and decreased FC between the right amygdala and the right orbitofrontal cortex (OFC) was found in smokers. In smokers, these amygdala measures did not correlate with any measures of cigarette use. The results revealed that the amygdala function but not volume was affected in nicotine addiction. When considering the fALFF and FC results, we propose that the OFC top-down control may regulate the amygdala activity in nicotine addicts. The pattern of amygdala-based FC in smokers revealed in our study may provide new information about the brain circuitry of tobacco dependence.
烟草使用障碍常与情绪障碍共病，彼此相互影响。杏仁核作为情绪处理的重要枢纽，可能在烟草成瘾中发挥关键作用。因此，我们旨在研究尼古丁依赖个体杏仁核的体积和自发活动及其与吸烟的关系。本研究共纳入 84 名吸烟者（年龄 22-54 岁）和 41 名非吸烟者（年龄 26-56 岁）。所有参与者均接受 3D-T1 加权图像和静息态 fMRI 图像采集。我们使用 ROI 体积、低频振幅（fALFF）和静息态功能连接（FC）来评估吸烟者杏仁核的结构和功能变化。吸烟者和非吸烟者的杏仁核体积无显著差异（p>0.05）。与非吸烟者相比，吸烟者右侧杏仁核的 fALFF 增加（p=0.024）。此外，吸烟者左侧杏仁核与右侧楔前叶之间的 FC 增加，右侧杏仁核与右侧眶额皮质（OFC）之间的 FC 减少。在吸烟者中，这些杏仁核测量值与吸烟量的任何测量值均无相关性。结果表明，尼古丁成瘾会影响杏仁核功能而非体积。考虑到 fALFF 和 FC 的结果，我们提出，OFC 的自上而下控制可能调节尼古丁成瘾者的杏仁核活动。我们研究中发现的基于杏仁核的 FC 模式可能为烟草依赖的大脑回路提供新信息。
