Cigarette Smoking and the Efficiency of the Frontoparietal Attentional Network

描述(申请人提供)：与突然戒烟相关的注意力缺陷导致戒烟困难。与急性戒烟有关的缺陷的神经基础还不是很清楚。额顶注意网络调节注意，并自上而下地控制感觉皮质的激活，包括梭形脸部区域。我们假设，突然戒烟会损害这一网络的功能效率，而急性尼古丁注射至少可以部分缓解这种损害。为了验证这一假设，我们开发了一个具有四个水平的注意/知觉负荷的选择性注意任务。它使用示意性图像作为目标和分心因素。与功能磁共振成像(FMRI)相结合，我们的任务将使我们能够评估注意/知觉负荷与额顶皮质和梭形面部区域fMRI信号与任务相关变化之间的关系。我们将研究20名吸烟者，并使用额顶皮质的负荷依赖性活动作为注意控制的指示，以及梭形脸部区域的负荷依赖性活动作为注意力控制有效性的指标。每个受试者将在三次fMRI会议(不同天)中进行研究，一次是在临时吸食安慰剂后，另一次是在戒酒(12小时)安慰剂后，其余的一次是在戒烟(12小时)尼古丁(4毫克)之后。我们预测，相对于随意吸食安慰剂后的激活，戒烟安慰剂戒烟者在低注意/感知负荷时，额顶叶皮质表现出更高的激活，而梭形脸部区域表现出类似的激活，随着任务负荷的增加，这些脑区的激活增加较少。我们还预测，相对于戒烟安慰剂戒烟后的激活，戒烟后的吸烟者在低任务负荷时，额顶皮质的激活程度更高，梭形脸部区域的激活程度相似，随着任务负荷的增加，这些脑区的激活程度也会更高。这项拟议研究的结果将阐明吸烟者的额顶注意网络功能如何受到突然戒烟和尼古丁注射的影响，并将提供一个工具，用于评估戒烟与其他因素(如性别和基因)的交互作用如何影响注意力。通过阐明戒断相关注意力缺陷的神经基础，这项工作可以帮助确定治疗目标，并可能找到治疗尼古丁依赖的新方法。

DESCRIPTION (provided by applicant): A deficit in attention associated with abrupt cessation of smoking contributes to the difficulty of smoking cessation. The neural basis of the deficit associated with acute smoking abstinence is not well understood. The frontoparietal attentional network mediates attention and exerts top-down attentional control over the activation of sensory cortex, including the fusiform face area. We posit that abrupt cessation of cigarette smoking impairs the functional efficiency of this network, and that acute nicotine administration at least partially alleviates this impairment. To test this hypothesis, we developed a selective attention task with four levels of attention/perception load. It uses schematic images efface as target and distracters. Paired with functional magnetic resonance imaging (fMRI), our task will allow us to assess the relations between attention/perception load and task- related changes of fMRI signal in the frontoparietal cortex and the fusiform face area. We will study 20 smokers, and use load-dependent activity in the frontoparietal cortex as an indication of attentional control, and load-dependent activity in the fusiform face area as an index of the effectiveness of attentional control. Each subject will be studied in three fMRI sessions (different days), one after smoking ad libitum + placebo, the other after abstinence (12 h) + placebo, and the remaining one after abstinence (12 h) + nicotine (4 mg). We predict that, relative to activation after smoking ad libitum + placebo, smokers after abstinence + placebo will show higher activation in the frontoparietal cortex and similar activation in the fusiform face area at low attention/perception load, and less increase in activation in these brain regions as task load is increased. We also predict that, relative to activation after abstinence + placebo, smokers after abstinence + nicotine will show higher activation in the frontoparietal cortex and similar activation in the fusiform face area at low task load, and greater increases in activation in these brain areas as task load is increased. The findings from the proposed research will clarify how the function of the frontoparietal attentional network of smokers is affected by abrupt cessation of smoking and by nicotine administration, and will also provide a tool for assessing how attention is affected by the interaction of smoking cessation with other factors, such as gender and genotype. By elucidating the neural substrates of impairments in withdrawal- associated deficits in attention, this work can help identify treatment targets and possibly new approches to therapy for nicotine dependence.