Paul Robert H, Grieve Stuart M, Niaura Raymond, David Sean P, Laidlaw David H, Cohen Ronald, Sweet Lawrence, Taylor George, Clark Richard C, Pogun Sakire, Gordon Evian
Department of Psychology, Behavioral Neuroscience, University of Missouri, St. Louis, MO 63121, USA.
Nicotine Tob Res. 2008 Jan;10(1):137-47. doi: 10.1080/14622200701767829.
Results from recent studies suggest that chronic cigarette smoking is associated with increased white matter volume in the brain as determined by in vivo neuroimaging. We used diffusion tensor imaging to examine the microstructural integrity of the white matter in 10 chronic smokers and 10 nonsmokers. All individuals were healthy, without histories of medical or psychiatric illness. Fractional anisotropy (FA) and trace were measured in the genu, body, and splenium of the corpus callosum. FA provides a measure of directional versus nondirectional water diffusion, whereas trace provides a measure of nondirectional water diffusion. Lower FA and higher trace values are considered to reflect less brain integrity. Voxel-based morphometry was used to define volumes in each of these regions of the corpus callosum. Chronic smokers exhibited significantly higher FA in the body and whole corpus callosum and a strong trend for higher FA in the splenium compared with nonsmokers. FA did not differ between groups in the genu, and neither trace nor white matter volumes differed between groups in any of the regions of interest. When subdivided by Fagerström score (low vs. high), the low Fagerström group exhibited significantly higher FA in the body of the corpus callosum compared with the high Fagerström group and the nonsmokers. These results suggest that, among healthy adults, lower exposure to cigarette smoking is associated with increased microstructural integrity of the white matter compared with either no exposure or higher exposure. Additional studies are needed to further explore differences in white matter integrity between smokers and nonsmokers.
近期研究结果表明，通过活体神经成像测定，长期吸烟与大脑白质体积增加有关。我们使用扩散张量成像来检查10名长期吸烟者和10名不吸烟者白质的微观结构完整性。所有个体均健康，无医学或精神疾病史。在胼胝体的膝部、体部和压部测量各向异性分数（FA）和迹值。FA提供了方向性与非方向性水扩散的测量指标，而迹值提供了非方向性水扩散的测量指标。较低的FA值和较高的迹值被认为反映了较低的脑完整性。基于体素的形态测量法用于确定胼胝体这些区域中每个区域的体积。与不吸烟者相比，长期吸烟者在胼胝体体部和整个胼胝体中的FA值显著更高，在压部中FA值也有升高的强烈趋势。两组在胼胝体膝部的FA值无差异，在任何感兴趣区域中，两组的迹值和白质体积均无差异。当按法格斯特罗姆评分（低与高）细分时，低法格斯特罗姆组在胼胝体体部的FA值显著高于高法格斯特罗姆组和不吸烟者。这些结果表明，在健康成年人中，与无暴露或高暴露相比，较低的吸烟暴露与白质微观结构完整性增加有关。需要进一步的研究来进一步探索吸烟者和不吸烟者之间白质完整性的差异。
