JW Kurzawski, K Mikellidou, MC Morrone, F Pestilli
The visual white matter connecting human area prostriata and the thalamus is retinotopically organized
Brain Structure and Function, 1-15
The human visual system is capable of processing visual information from fovea to the far peripheral visual feld. Recent fMRI studies have shown a full and detailed retinotopic map in area prostriata, located ventro-dorsally and anterior to the calcarine sulcus along the parieto-occipital sulcus with strong preference for peripheral and wide-feld stimulation. Here, we report the anatomical pattern of white matter connections between area prostriata and the thalamus encompassing the lateral geniculate nucleus (LGN). To this end, we developed and utilized an automated pipeline comprising a series of Apps that run openly on the cloud computing platform brainlife.io to analyse 139 subjects of the Human Connectome Project (HCP). We observe a continuous and extended bundle of white matter fbers from which two subcomponents can be extracted: one passing ventrally parallel to the optic radiations (OR) and another passing dorsally circumventing the lateral ventricle. Interestingly, the loop travelling dorsally connects the thalamus with the central visual feld representation of prostriata located anteriorly, while the other loop travelling more ventrally connects the LGN with the more peripheral visual feld representation located posteriorly. We then analyse an additional cohort of 10 HCP subjects using a manual plane extraction method outside brainlife.io to study the relationship between the two extracted white matter subcomponents and eccentricity, myelin and cortical thickness gradients within prostriata. Our results are consistent with a retinotopic segregation recently demonstrated in the OR, connecting the LGN and V1 in humans and reveal for the frst time a retinotopic segregation regarding the trajectory of a fber bundle between the thalamus and an associative visual area.