The topology of interhemispheric connection of human primary visual cortex
Poster No:
2071
Submission Type:
Abstract Submission
Authors:
Jiaowen Wang1, Shishuo Chen1, Yanming Wang1, Bensheng Qiu1, Yifeng Zhou1, Hao Wang1, Xiaoxiao Wang1
Institutions:
1University of Science and Technology of China, Hefei, Anhui
First Author:
Co-Author(s):
Introduction:
The left and right primary visual cortices are connected by the forceps major (Fmajor). However, its functional topology remains poorly understood. Thus, we conducted a comprehensive analysis of the visual field representation within the FMajor in the human visual system using 7T retinotopic fMRI data from the Human Connectome Project.
Methods:
A single voxel within the Fmajor may contain populational receptive field (pRF) of bilateral visual field. Thus, we employ a Bayesian pRF framework to compare single, dual, or triple pRF models. Guided by Occam's razor principle, the framework identifies the most likely model at each voxel. To validate the results, we also trace mices' visual hemispheric connections by injecting viruses expressing fluorescent proteins (rAAV-hSyn-mCherry and rAAV-hSyn-EGFP) into bilateral V1 of mice, respectively. The research was approved by the research ethics board of USTC (USTCACUC21240122009).
Results:
The results show that the single RF model dominated in the most of the voxels, followed by the dual RF model more prevalent in voxels close to the occipital white/gray matter interface in the FMajor (Fig 1A). Notably, a clustered mapping pattern emerges, characterized by a "sandwich" contralateral-ipsilateral-contralateral distribution of pRF in both the left and right hemispheres (Fig 1B, the polar angle column), suggesting an ipsihemispheric-contrahemispheric-ipsihemispheric bundled projection of the FMajor. Moreover, a peri-fovea and peripheral dominant eccentricity maps are observed in the Fmajor (Fig 1B. the eccentricity column), showing that the foveal bilateral information is not carried by the visual callosal connection. The "sandwich" pattern is reproduced in functional connectivity gradient analysis of the retinotopy data (Fig 1D). The dual pRFs are dominated by the contralateral visual field, with the fellow pRF to the bilateral visual field (Fig 2A), and show contralateral visual field dominant (Fig 2B-D). Both across-subjects and across-TRs-runs split half analysis show high cosistancy with the whole dataset, shows the reliability of the pRF model (Fig 2G). In the mouse brain, nerve fiber bundles labeled by the two viruses are observed to be parallel on both sides of the corpus callosum (Fig 2, H-J), consistent with the "sandwich" structure within human FMajor.
·Figure 1. 1pRF and 2pRF results.
·Figure 2. The 2pRF results and validations.
Conclusions:
With the help of fMRI, this study succeeds in investigating the projecting direction of the bundles in Fmajor, and finds a "sandwich" structure, which is also observed in the mouse brain. A peripheral prefering eccentricity map is also observed in the FMajor. These findings may provide crucial insights into the topological organization of cerebral interhemispheric connectivity.
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI) 2
Univariate Modeling
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
White Matter Anatomy, Fiber Pathways and Connectivity
Perception, Attention and Motor Behavior:
Perception: Visual 1
Keywords:
Other - populational receptive field; visual cortex; forceps major; corpus callosum; fiber tract tracing
1|2Indicates the priority used for review