Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892, USA.
Alcohol Clin Exp Res. 2010 Feb;34(2):331-41. doi: 10.1111/j.1530-0277.2009.01095.x. Epub 2009 Nov 24.
Alcoholism is often associated with impaired emotional control. Alcoholics have also been found to have deficits in frontal lobe executive functions. Recent functional imaging studies have suggested that alcoholics show greater activation than nonalcoholics in circuits involving frontal lobes, as well as more posterior brain regions, when engaged in executive-type tasks. In this study, we compared brain activations of alcohol-dependent patients and healthy nonalcoholics while they performed 2 simple judgment tasks designed to activate frontal circuits involved in a basic form of decision making. Participants completed 1 judgment task that required an emotional judgment and 1 task that did not, which enabled us to study whether alcoholics had greater brain activation while performing executive tasks, and to determine if emotional tasks elicited even greater activation than nonemotional tasks.
We performed functional magnetic resonance imaging scans while alcoholic patients and nonalcoholic controls viewed pictures from the International Affective Picture System. In 3 separate runs, participants viewed the images without making a judgment, determined whether the images were indoor or outdoor scenes, or decided if they liked or disliked the images.
There was little difference in brain activation between alcoholics and controls when no judgment was required. When participants made judgments about either the location or whether they liked or disliked an image, however, we observed significantly increased activation in frontal, limbic, and temporal regions in the patients relative to the controls. Increases were particularly robust in the frontal lobe and in areas of the brain associated with language. When we compared the emotional to the nonemotional judgment, the alcoholics, but not the controls, showed greater activation in the ventral mesial frontal cortex.
Alcoholic patients appear to use brain language areas more than nonalcoholics while making judgments about the setting or liking of emotionally arousing visual images. This increased activation may reflect a compensatory recruitment of brain regions to perform simple decision-making tasks.
酗酒常伴有情绪控制障碍。研究还发现，酗酒者额叶执行功能也存在缺陷。最近的功能影像学研究表明，当执行执行类型任务时，酗酒者在涉及额叶的回路以及更多的后脑区域比非酗酒者表现出更大的激活。在这项研究中，我们比较了酒精依赖患者和健康非酗酒者的大脑激活情况，当他们执行 2 项旨在激活涉及基本决策形式的额叶回路的简单判断任务时。参与者完成了 1 项需要情感判断的判断任务和 1 项不需要的任务，这使我们能够研究酗酒者在执行执行任务时是否有更大的大脑激活，以及确定情感任务是否比非情感任务引起更大的激活。
我们在酒精依赖患者和非酒精对照者观看国际情感图片系统的图片时进行了功能磁共振成像扫描。在 3 个单独的运行中，参与者在不进行判断的情况下观看图像，确定图像是室内还是室外场景，或者决定他们是否喜欢或不喜欢图像。
当不需要判断时，酗酒者和对照组之间的大脑激活几乎没有差异。然而，当参与者对位置或喜欢或不喜欢图像做出判断时，我们观察到患者的额叶、边缘和颞叶区域的激活明显增加。在额叶和与语言相关的大脑区域增加尤为明显。当我们将情感判断与非情感判断进行比较时，只有酗酒者而不是对照组在腹内侧额叶皮层表现出更大的激活。
在对情绪唤起的视觉图像的环境或喜好做出判断时，酒精依赖患者似乎比非酒精依赖者更多地使用大脑语言区域。这种增加的激活可能反映了大脑区域的代偿性招募，以执行简单的决策任务。
