Figure 1. A flow chart of the neural genetic investigation analysis for language. A, The definition of language activation regions and language genetic clusters. The top-right panel displays the language activation map, which was derived from the HCP language fMRI task. In this task, subjects listened to stories adapted from Aesop's fables and answered questions related to them (as shown in the top-left panel). The language map was further subdivided into 40 regions using the Brainnetome Atlas (Fan et al., 2016). For each region, genetic modeling was performed, and the regions with a genetic factor (A or D) were identified as genetically influenced language regions. Then, 25 genetically influenced language regions were merged based on neural activation, resulting in six language genetic clusters (as shown in the bottom-right panel). Slice views and projected brain images were prepared in MRIcron (https://www.nitrc.org/projects/mricron) and BrainNet Viewer (Xia et al., 2013), respectively. B, Gene expression analyses of language clusters. The left panel displays the region × gene expression matrix, which was generated through multiple preprocessing steps and used for subsequent analyses. Two types of decoding were conducted: decoding between genetically influenced language regions and nonlanguage regions to test whether the language genetic clusters exhibited systematically different genetic profiles compared with the rest of the brain and decoding among different language genetic clusters to examine differences among language genetic clusters. The genes that contributed to these two classifications were identified accordingly. C, The investigation of genetic factors for multiple object domains. The genetic impact of each language cluster on various object domains, including tools, body parts, and faces, was evaluated using the HCP working memory task. In this task, subjects viewed pictures from four object domains (i.e., tools, faces, body parts, and places; Barch et al., 2013) over two runs (shown in the left panel). To avoid the influence of working memory and focus on our interests, tools, body parts, and faces, whole-brain contrast images of these three object domains versus places were calculated and measured at the individual level after model estimation. Multiple lines of analyses (shown in the right panel) were conducted to further test the genetic relationship between language and other object domains for each language genetic cluster. The first validation analysis tested whether each language cluster exhibited a genetic effect on specific object domains when the analyses were restricted to the “language genetic voxels.” The second validation analysis investigated whether there were common factors influenced by genetics between language and specific object domains with the existing genetic influence through the CP model.