Interhemispheric functional connectivity of the ventral occipitotemporal cortex supports Chinese reading.

Previous studies have revealed the involvement of the bilateral ventral occipitotemporal cortex (vOT) in word reading, especially in Chinese character reading. However, the interhemispheric communication mechanisms of the bilateral vOT and how they work in Chinese character reading have not been fully investigated. Two experiments were conducted in this study to address those questions using resting-state and task-based fMRI. Experiment 1 revealed stronger interhemispheric resting-state functional connectivity (rsFC) in the posterior vOT subregion compared to the middle and anterior subregions and a significant positive correlation with Chinese reading efficiency in the posterior subregion. Experiment 2 further explored the effective connectivity in the Chinese rhythm and semantic judgment tasks using dynamic causal model analysis. Results showed significant interhemispheric intrinsic connections similar to those in the resting state in the posterior subregion and right-to-left modulatory connections in the middle and anterior subregions. In addition, stronger right-to-left modulatory connectivity in the anterior subregion was associated with better behavioral performance in the semantic judgment task. These convergent findings highlight the importance of interhemispheric communication of the bilateral vOT in Chinese character reading.