Connectivity-based Parcellation Of The Human Fusiform Gyrus

The ventral information processing stream of human visual system which travels from occipital cortex to anterior temporal cortex is highly response to object identification and recognition. The fusiform gyrus(FG), locating in the middle of ventral temporal cortex, is one of the most important brain area in visual ventral stream. It has been well established that fusiform gyrus takes part in a range of different visual cognitive functions, such as recognition of face, body parts, word-form and other object features. Recently, several studies indicated that functional activity of the FG was highly corresponding to the language performance, which together with the anterior-posterior streamline of visual system in human ventral temporal cortex, suggested a complex semantic knowledge processing in this area. Given its complex and diverse functions, a more fine-grained parcellation scheme for the FG should be proposed to better understand its functional organization and connectivity properties.However, the parcellation scheme of the FG adapted with its functional heterogeneity has not been well established. In the current study, we sought to present a consistent parcellation of the FG based on its distinct connectivity pattern in two independent datasets by using diffusion tensor imaging. We explored the whole brain anatomical and resting-state functional connectivity patterns in the FG and its involvement of functional sub-networks. Besides, the meta-data analysis was also performed to further evaluate functional characterizes for each subregion.As a result, three distinct subregions were identified in the FG, including the medial part(FGm) which served as a transition region combining multiple stimuli, the lateral part(FGl) which was responsible for categorical recognition and the anterior part(FGa) which was involved in semantic understanding. This research supported two organizational functional transitions of ventral temporal gyrus, the posterior/anterior direction of visual/semantic processing and the media/lateral direction of high-level visual processing. Our proposed parcellation scheme may facilitate more detailed study of the human FG in the future.