腹侧颞叶皮层功能组织的解剖支撑

The ventral temporal cortex (VTC), where high-level visual regions reside, plays a key role in object recognition. Three key principles have been revealed for the functional organization of the VTC. First, multiple functional representations are superimposed on the same cortical expanse. Second, functional areas which represent different visual attributes are spatially segregated. Finally, functional integration happens in the functional areas which prefer the same and even different visual attributes. Although great advances have been made in understanding the functional organization of the VTC, little is known about the anatomical basis for its functional organization. Here, we combine in vivo multi-modal magnetic resonance imaging (MRI), in vitro cytoarchitecture imaging and computational modeling to investigate the neuroanatomical basis underling the VTC’s functional organization. Specifically, we’ll use natural stimulus functional MRI to characterize the VTC’s functional representation fingerprints and functional connectivity fingerprints, use structural MRI and diffusion MRI to measure the VTC’s macroscopic morphological fingerprints and white-matter connectivity fingerprints, and use the public in vitro cytoarchitecture dataset (BigBrain, https://bigbrain.loris.ca/) to characterize the VTC’s microscopic morphological fingerprints. Then, we’ll build quantitative prediction model to evaluate how the VTC’s morphological fingerprints and white-mater connectivity fingerprints determine its functional representation fingerprints and functional connectivity fingerprints, and to answer the following key questions: (1) How do the VTC’s morphological fingerprints and white-matter connectivity fingerprints relate to its functional representation fingerprints? (2) What is the morphological and connectivity basis for the VTC’s functional segregation and integration? (3) To what extent do the morphological and white-matter connectivity fingerprints constrain the topological organization of the VTC?

腹侧颞叶皮层作为高级视觉加工的功能单元，呈现出功能叠加、功能分离和功能集成三大组织特征，然而我们对这些功能组织背后的解剖支撑仍所知甚少。本项目将综合在体多模态磁共振成像、离体细胞构筑结构成像和定量计算模型对腹侧颞叶皮层功能组织背后的脑区形态和脑区间白质连接特征进行研究。具体而言，我们将采用自然刺激功能磁共振实验，全面刻画腹侧颞叶皮层功能表征指纹和功能连接指纹；采用结构磁共振，刻画腹侧颞叶皮层宏观形态指纹；采用弥散加权磁共振纤维追踪，刻画腹侧颞叶皮层白质连接指纹；采用国际公开细胞构筑结构数据集，刻画腹侧颞叶皮层微观形态指纹。进而基于皮层宏观形态指纹、微观形态指纹和白质连接指纹构造预测模型，定量考察腹侧颞叶皮层的解剖结构如何决定：1）腹侧颞叶皮层对不同维度客体属性的反应强度（功能叠加）；2）腹侧颞叶皮层中不同功能区的空间拓扑（功能分离）；3）腹侧颞叶皮层中不同脑区的功能交互（功能集成）。

腹侧颞叶皮层作为高级视觉加工的功能单元，呈现出功能叠加、功能分离和功能集成三大组织特征，然而我们对这些功能组织背后的解剖支撑仍所知甚少。本项目综合在体多模态磁共振成像、离体细胞构筑结构成像、基因转录组数据和定量计算模型对腹侧颞叶皮层功能组织背后的脑区结构形态和连接特征进行了刻画，并揭示了腹侧颞叶皮层的结构形态指纹和白质连接指纹如何支撑腹侧颞叶皮层的功能组织。取得了系列结果： 1) 通过任务fMRI构建了腹侧颞叶脑功能区图谱，并证明基于细胞构筑结构、视网膜拓扑、脑区连接构建的脑区图谱和脑功能区图谱间具有很好的对应性，表明腹侧颞叶脑区的功能区位置在很大程度上是由其结构和连接指纹所决定；2) 采用公开的全脑基因转录数据集，揭示了无论是脑区间的层级组织，还是脑区内的精细组织均存在底层基因表达梯度与之对应，且脑区间和脑区内梯度基因几乎没有重叠。3) 通过海量自然刺激fMRI实验，发现腹侧颞叶皮层对客体生命性和客体大小形成了完整的四分编码组织规律，而不是之前基于少量人造刺激下观察到的对生命客体、无生命小客体和无生命大客体的三分编码组织规律。4) 通过对深度卷积神经网络的反向工程，发现DCNN各层都采用了稀疏编码方案，且稀疏程度沿层次结构增加，提示人脑枕颞叶皮层可能也采用类似的编码机制进行功能组织。