人脑同伦功能亲和度图谱

Human brain mapping of homotopic functional affinity

人脑左右半球中空间对等的区域亦称同伦脑区,往往表现出功能相似性,即功能同伦.为理解人类心理行为的功能同伦规律和机制,本文基于脑连接组的双因子生成理论,提出一种人脑功能同伦研究方法:同伦功能亲和度.该方法通过计算同伦脑区的全脑功能连接模式的余弦距离,量化同伦脑区的功能亲和度.使用美国和中国“人脑连接组计划”的全脑功能磁共振影像数据库,首先绘制了“700毫秒-2毫米”时空精度的同伦功能亲和度图谱,评估了其个体差异的重测信度.其次,对该图谱的系统分析定位出人类颞顶联合区的3个特定区域,并发现了其半球偏侧化的特征规律,揭示了与注意、语言和社会认知的功能关联.最后,通过多模态脑图谱关联分析进一步探索了人脑同伦功能亲和度与遗传、进化、结构与功能组织分布的相关规律.综上,本文所提出的同伦功能亲和度方法可为人口神经科学研究提供高信效度人脑功能测量图谱.

Homotopic positions are defined as the two areas with opposite but equal horizonal coordinates in the standard symmetric brain space.Characterizing similarity between two homotopic areas,brain homotopy represents a typical feature of the brain’s two hemispheres for both structure and function.Functional homotopy provides important perspectives for understanding neural correlates of cognition and behavior.Despite the decisive role of spatial geometric constraints and homophilic attachment on the human connectome,traditional practices in mapping functional homotopy only considered the temporal correlations of functional timeseries between homotopic areas,but ignored the homophily factors in generative connectivity models.Here,we proposed a novel method for functional homotopy analysis,namely Homotopic Functional Affinity(HFA).This method quantifies the homotopic affinity as the Cosine distance of the full-brain functional connectivity profiles or fingerprints between the homotopic areas.HFA captures both geometric constraints(homotopic location)and homophily(affinity)simultaneously.By leveraging the resting-state functional magnetic resonance imaging data from the Human Connectome Project(HCP)and the Chinese HCP(CHCP),we mapped the 700 ms-2 mm high spatiotemporal resolution HFA and evaluated its test-retest reliability with linear mixed models,exhibiting generally fairto-substantial reliable measurements of individual differences in HFA.The lowest HFA observed in the temporo-parietal junction(TPJ)inspired to perform an edge-detection algorithm on its surface render and derived three clearly differentiable and adjacent TPJ subregions:the anterior TPJ(TPJa),the central TPJ(TPJc),and the posterior TPJ(TPJp).We further validated the HFA for the three TPJ regions through a set of comprehensive analyses,including the delineation of their functional connectivity fingerprints,the meta-analysis of their cognitive functions,and their task-activation correlation.Finally,we linked the cortical HFA map to those multimodal brain maps of gene expression,evolution,myelination,functional hierarchy,and cognitive association.The systematic subregion analysis revealed the complex hemispheric specialization of TPJ in attention,social cognition,and language functions.In general,functional specialization of the TPJ areas was stronger in the left hemisphere.The findings from the task activation correlation were highly consistent with those of the meta-analysis.Notably,there were significant differences in social cognition relevant to the three TPJ areas between HCP and CHCP datasets.Furthermore,the correlation analysis of multimodal brain maps illustrated a close relationship between the HFA map and multimodal brain maps.The consistency of maps derived in distinct analyses demonstrated the feasibility of HFA in further understanding psychological and behavioral mechanisms on neural lateralization from the perspective of hemispheric functional integration and specialization.We believe that HFA will create a new arena for brain mapping in population neuroscience studies.