Abstract
Area prostriata preferentially responds to very fast motion, greater than 500 deg/sec, and has a complete representation of the visual field, similarly to all known visual areas, however it does not follow the traditional cortical magnification rule. Instead, it has a strong preference for peripheral and wide-field stimulation. A full-map of the structural connections of prostriata is currently unreported in the human brain. We investigated the connectivity between area prostriata and the visual thalamus, specifically the lateral geniculate nucleus (LGNs). We combined four data modalities (T1- and T2-weighted anatomical images, functional population receptive field (pRF) mapping and ensemble tractography) together with statistical evaluation methods on data from the Human Connectome Project (HCP). Structural and functional data were integrated to characterize the corticothalamic connections of area prostriata. We observe a continuous and structurally complex bundle of white matter fibers which were arbitrarily subdivided into two sub-components: one passing ventrally parallel to the optic radiations (OR) and another circumventing the lateral ventricle. Interestingly, whereas the loop travelling more superiorly transfers information between the LGN and prostriata directed to the central visual field, the other sub-tract travelling inferiorly along the OR transfers information from the peripheral visual field. This result is consistent with a retinotopic segregation also demonstrated in the OR which connects the LGN and V1 in humans. Our results demonstrate for the first time such a segregation in a fiber bundle connecting the thalamus with an associative visual area.