Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, University of Heidelberg, Square J5, 68159 Mannheim, Germany.
Neuroimage. 2012 Jan 16;59(2):1949-59. doi: 10.1016/j.neuroimage.2011.09.008. Epub 2011 Sep 13.
Response inhibition is thought to depend critically on the inferior frontal gyrus, pars opercularis (IFGoper), presupplementary motor area (preSMA) and basal ganglia, including the subthalamic nucleus (STN), but the differential contribution of structural connections within this network to response inhibition remains unclear. Using diffusion tensor imaging and probabilistic fiber tractography, we investigated the relative associations between local white matter microstructure and stop-signal response inhibition in fronto-basal ganglia tracts delineated by probabilistic tractography. In a tract-of-interest approach, we identify significant associations with fractional anisotropy (FA) in fibers connecting the right STN region to both preSMA/SMA and IFGoper and in bilateral tracts connecting preSMA/SMA to IFGoper and the striatum. In addition, significant associations with radial diffusivity (RD) were found in fibers connecting the right preSMA/SMA to striatum and in bilateral tracts between IFGoper and STN region. In our whole-brain analysis, additional significant clusters were identified in the corpus callosum, optic radiation, inferior fronto-occipital tract and white matter of the precentral gyrus. To investigate the relative importance of regional white matter characteristics to response inhibition performance, we performed a step-wise multiple regression analysis that yielded FA in tracts connecting preSMA/SMA to the STN region and striatum, respectively, and RD in fibers connecting IFGoper to the STN region as best predictors of response inhibition performance (42% explained variance). These findings point to a specific contribution of white matter pathways connecting distinct basal ganglia structures with both medial frontal and ventrolateral prefrontal regions to response inhibition.
反应抑制被认为主要依赖于额下回眶部（IFGoper）、补充运动区（preSMA）和基底节，包括丘脑底核（STN），但该网络内的结构连接对反应抑制的差异贡献仍不清楚。使用弥散张量成像和概率纤维追踪技术，我们研究了局部白质微观结构与通过概率纤维追踪技术描绘的额基底节束之间的停走信号反应抑制之间的相对关联。在关注束的方法中，我们确定了与连接右侧 STN 区域到 preSMA/SMA 和 IFGoper 的纤维的各向异性分数（FA）以及连接 preSMA/SMA 到 IFGoper 和纹状体的双侧纤维之间存在显著关联。此外，还发现连接右侧 preSMA/SMA 和纹状体的纤维以及 IFGoper 和 STN 区域之间的双侧纤维与径向扩散系数（RD）存在显著关联。在全脑分析中，还在胼胝体、视辐射、下额枕束和中央前回白质中确定了额外的显著聚类。为了研究区域白质特征对反应抑制性能的相对重要性，我们进行了逐步多元回归分析，分别得到了连接 preSMA/SMA 到 STN 区域和纹状体的纤维的 FA，以及连接 IFGoper 到 STN 区域的纤维的 RD，作为反应抑制性能的最佳预测因子（解释了 42%的方差）。这些发现表明，连接不同基底节结构与内侧额前区和腹外侧前额叶区的白质通路对白质对反应抑制有特定的贡献。
