Anatomical connections underlying personally-familiar face processing

The second level analysis allowed the definition of functional activated areas related to the evaluated task. For the core system, functional ROIs were obtained directly from the t-contrast defined as unfamiliar faces > houses what evinced face-selective areas (p<0.05 uncorrected). The extended system ROIs were obtained from the contrast familiar faces > unfamiliar faces which uncover those areas related to familiarity processing (p-value<0.05 uncorrected). This relaxed p-value was used to avoid the dilatation of the ROIs into the white matter to maximize contact with streamlines during tractography. The MarsBaR toolbox (http://marsbar.sourceforge.net/) was used for defining the functional ROIs from these previous contrasts. The resulting regions from the contrasts unfamiliar faces > houses were OFA/FFA (left and right) and STSp (left and right) representing core system, while familiar faces > unfamiliar faces uncovered the mOF/AC, MC, PC, left and right Ins, belonging to the extended system of face processing. The resulting probabilistic tracking among this ROIs is store in .mat files for each subject and for both scanner (Siemens and GE) used in this study, and for the validation data as well (MGH). The matrix order is: CA, CM, CP, Ins_L, Ins_R, OFA_FFA_L, OFA_FFA_R, STSp_L, STSp_R, Vis. For further details refers to the original paper published by PlosOne (insert reference when the paper is published)

二级分析可用于定义与所评估任务相关的功能激活脑区。针对面孔加工的核心系统，功能感兴趣区（Region of Interest, ROI）直接通过定义为“陌生面孔>房屋”的t检验对比（t-contrast）获取，该对比可识别出面孔选择性脑区（未校正p<0.05）。针对面孔加工的扩展系统，功能感兴趣区则通过“熟悉面孔>陌生面孔”的对比获取，该对比可揭示与熟悉度加工相关的脑区（未校正p<0.05）。采用该宽松的p值阈值，可避免将感兴趣区扩张至白质，从而在纤维束追踪（tractography）过程中最大化与神经纤维束的接触面积。本研究使用MarsBaR工具箱（http://marsbar.sourceforge.net/）从上述对比中提取功能感兴趣区。由“陌生面孔>房屋”对比得到的脑区为双侧OFA/FFA与双侧STSp，属于面孔加工的核心系统；而“熟悉面孔>陌生面孔”对比揭示的脑区则为mOF/AC、MC、PC以及双侧脑岛，归属于面孔加工的扩展系统。上述感兴趣区间的概率纤维束追踪结果已存储为.mat格式文件，涵盖本研究中所有被试、所用的两种扫描仪（西门子Siemens、通用电气GE）的数据，同时也包含验证数据集（麻省总医院Massachusetts General Hospital, MGH）的数据。矩阵顺序如下：CA、CM、CP、左侧脑岛、右侧脑岛、左侧OFA/FFA、右侧OFA/FFA、左侧STSp、右侧STSp以及视觉皮层（Vis）。如需进一步了解细节，请参阅发表于PLOS ONE期刊的原创论文（论文正式发表后将补充参考文献信息）