Department of Behavioral Science-Unit 1330, The University of Texas MD Anderson Cancer Center, PO Box 30149, Houston, TX 77230, USA.
Eur J Neurosci. 2011 Dec;34(12):2054-63. doi: 10.1111/j.1460-9568.2011.07915.x. Epub 2011 Nov 20.
Chronic smoking is thought to cause changes in brain reward systems that result in overvaluation of cigarette-related stimuli and undervaluation of natural rewards. We tested the hypotheses that, in smokers, brain circuits involved in emotional processing: (i) would be more active during exposure to cigarette-related than neutral pictures; and (ii) would be less active to pleasant compared with cigarette-related pictures, suggesting a devaluation of intrinsically pleasant stimuli. We obtained whole-brain blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging data from 35 smokers during the presentation of pleasant (erotica and romance), unpleasant (mutilations and sad), neutral, and cigarette-related pictures. Whole-brain analyses showed significantly larger BOLD responses during presentation of cigarette-related pictures relative to neutral ones within the secondary visual areas, the cingulate gyrus, the frontal gyrus, the dorsal striatum, and the left insula. BOLD responses to erotic pictures exceeded responses to cigarette-related pictures in all clusters except the insula. Within the left insula we observed larger BOLD responses to cigarette-related pictures than to all other picture categories. By including intrinsically pleasant and unpleasant pictures in addition to neutral ones, we were able to conclude that the presentation of cigarette-related pictures activates brain areas supporting emotional processes, but we did not find evidence of overall reduced activation of the brain reward systems in the presence of intrinsically pleasant stimuli.
慢性吸烟被认为会导致大脑奖励系统发生变化，从而导致对与香烟相关的刺激的高估和对自然奖励的低估。我们测试了以下假设：在吸烟者中，涉及情绪处理的大脑回路：（i）在暴露于与香烟相关的图片时会比中性图片更活跃；（ii）与香烟相关的图片相比，对愉快的图片的活跃度会降低，表明对内在愉快的刺激的评价降低。我们从 35 名吸烟者获得了整个大脑血氧水平依赖性（BOLD）功能磁共振成像数据，这些吸烟者在呈现愉快（色情和浪漫）、不愉快（残缺和悲伤）、中性和与香烟相关的图片时。全脑分析显示，在呈现与香烟相关的图片时，相对于中性图片，在次要视觉区域、扣带回、额回、背侧纹状体和左侧岛叶中，BOLD 反应明显更大。在所有除了岛叶的集群中，色情图片的 BOLD 反应都超过了与香烟相关的图片。在左侧岛叶中，我们观察到与香烟相关的图片比其他所有图片类别引起更大的 BOLD 反应。通过除了中性图片之外还包括内在愉快和不愉快的图片，我们能够得出结论，呈现与香烟相关的图片会激活支持情绪处理的大脑区域，但我们没有发现在存在内在愉快刺激时大脑奖励系统整体激活降低的证据。
