Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA 90095, USA.
Neuropsychopharmacology. 2010 Feb;35(3):775-82. doi: 10.1038/npp.2009.186. Epub 2009 Nov 11.
Prior research suggests that abrupt initiation of abstinence from cigarette smoking reduces neural cognitive efficiency. When cognitive efficiency is high, processing speed and accuracy are maximized with minimal allocation of cognitive resources. The study presented here tested the effects of resumption of smoking on cognitive response conflict after overnight abstinence from smoking, hypothesizing that smoking would enhance cognitive efficiency. Twenty paid research volunteers who were chronic cigarette smokers abstained from smoking overnight (>12 h) before undergoing fMRI while performing a color-word Stroop task during two separate test sessions: one that did not include smoking before testing and another one that did. Statistical analyses were performed by modeling the Stroop effect (incongruent >congruent) BOLD response within a collection of a priori regions of interest that have consistently been associated with cognitive control. Behavioral assessment alone did not reveal any significant differences in the Stroop effect between the two sessions. BOLD activations, however, indicated that in the right anterior cingulate cortex (ACC), smokers had significantly less task-related activity following smoking (p<0.02). In contrast, the right middle frontal gyrus exhibited significantly greater activity after smoking as compared to the no-smoking session (p<0.003). Exaggerated neural activity in the ACC during nicotine withdrawal may reflect a compensatory mechanism by which cognitive control networks expend excessive energy to support selective attention processes. Resumption of smoking may enhance cognitive control in smokers, involving a reduction in ACC response conflict activity together with improvement in conflict resolution involving the dorsolateral prefrontal cortex.
先前的研究表明，突然戒烟会降低神经认知效率。当认知效率较高时，处理速度和准确性达到最高，认知资源的分配也最少。本研究测试了在一夜戒烟后恢复吸烟对认知反应冲突的影响，假设吸烟会提高认知效率。20 名有偿研究志愿者为慢性吸烟者，在进行 fMRI 扫描前的一夜之间（超过 12 小时）戒烟，并在两次单独的测试会议期间执行颜色-单词斯特鲁普任务：一次不包括测试前吸烟，另一次包括。通过对一致与认知控制相关的一系列事先确定的感兴趣区域内的斯特鲁普效应（不一致>一致）BOLD 反应进行建模，进行了统计分析。仅行为评估并未显示两次会议之间的斯特鲁普效应有任何显着差异。然而，BOLD 激活表明，在右侧前扣带皮层（ACC）中，吸烟者在吸烟后与吸烟前相比，任务相关的活动显着减少（p<0.02）。相比之下，右中额回在吸烟后表现出比不吸烟会议更大的活动（p<0.003）。尼古丁戒断期间 ACC 中过度的神经活动可能反映了一种补偿机制，即认知控制网络消耗过多的能量来支持选择性注意过程。恢复吸烟可能会增强吸烟者的认知控制，涉及减少 ACC 反应冲突活动，同时改善涉及背外侧前额叶皮层的冲突解决。
