Foveal Representation In Visual Cortex Of Human Based On Ultra-high Filed Magnetic Resonance Imaging

The human visual filed include the visual range of the central area(0°-1.7 °)?the near central area(1.7 °-5 °),the vertical direction 124 ° and the horizontal direction of 188 ° of the surrounding area.The area is what people pay attention to,that is,the area of line of sight lock.The fovea projects at the foveal retina,where it is responsible for the fine processing of areas of human interest.In the past,due to the influence of resolution and large vascular noise of cortex,it was difficult to accurately map the central cortical representation and calculate the important indexes such as cortical thickness and gray matter volume.In this paper,with the help of the first ultra-field MRI scanner with active shielding in China,combined with the careful optimization of visual stimuli,the structure image with the resolution of 0.5*0.5*0.5mm3 and the functional images of 1.6*1.6*1.6mm3,which solved previous problems.In this paper,we first conducted a full pre-experiment to optimize the experimental conditions,scanning parameters,visual stimuli parameters and data processing steps and methods.The data were cleaned under rigorous examination.After preprocessing,the topological map was extracted by phase method,patchy gray and gray matter-pial boundary were patched with patch curvature method,cortical thickness was determined by space finding default model network,T test to determine the effectiveness of data differences and other methods.This article conducted a survey of 10 normal visual volunteers and completed the data analysis.This part is the main content of this article.We have got the retinotopic map of 10 subjects in the field of view of 0?5°.Also,we calculated the cortical magnification,cortical thickness and gray matter volume,and compared the fovea and near fovea on resting brain network.The study found that the fovea compared to the near foveal,the cortical magnification showed a non-linear growth,resting brain network is more abundant.There was no significant difference in cortical thickness between the two groups.Finally,this article invited 3 macular degeneration volunteers to do supplementary control experiment.The experiment found that compared to normal vision volunteers,macular degeneration makes the original foveal visual cortex thinning,profovea layer thickening,and resting brain network also occurred "moving",which lead us to a significant phenomenon:visual compensation.