The visual white matter connecting human area prostriata and the thalamus is retinotopically organized

Abstract

The human visual system is capable of processing visual information from fovea to the far peripheral visual field. 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 parietooccipital sulcus with strong preference for peripheral and wide-field stimulation. Here, we report the anatomical pattern of white-matter connections between area prostriata and the thalamus encompassing the lateral geniculate nucleus (LGN). We observe a continuous and extended bundle of white matter fibers 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 field representation of prostriata, while the other loop travelling more ventrally connects the LGN with the more peripheral visual field representation. This is consistent with a retinotopic segregation recently demonstrated in the OR, connecting the LGN and V1 in humans. Our results demonstrate for the first time a retinotopic segregation regarding the trajectory of a fiber bundle between the thalamus and an associative visual area.

Retinotopic organization of feedback projections in primate early visual cortex: implications for active vision

“…Tracer studies reveal connections with the peripheral representation of the early visual cortex in macaque (Sousa et al, 1991) and rodent (Lu et al, 2020). In rodents and perhaps in humans, prostriata receives a direct input from the dorsal lateral geniculate (Chen et al, 2021; Kurzawski et al, 2020). In addition to the projection from prostriata we found a considerably weaker projection from the retrosplenial area 23, which has also been proposed to constitute a primate visual motion area (Smith, 2021).…”

Edges in brain networks: Contributions to models of structure and function

“…When visualizing networks, often edges are represented as straight lines through space, with thicknesses or transparency that denotes edges strength. However, we should not lose sight that this representation is divergent from the anatomical reality of the brain, which is embedded in space and contains topographically organized white matter connections (Jbabdi, Sotiropoulos et al 2015, Kurzawski, Mikellidou et al 2020. Structural edges travel along physical paths through the white matter that have shape, curvature, and volume, and that compete for physical space and limited metabolic resources.…”

Chemoarchitecture of area prostriata in adult and developing mice: Comparison with presubiculum and parasubiculum

“…Finally, it should be noted that data are not yet available for afferent connections of the prostriata in nonhuman primates. In human brains, one tractography study indicates the existence of direct projections from the DLG to the prostriata (Kurzawski et al., 2020), and this finding has been confirmed in rats and mice with direct tract‐tracing methods (Chen et al., 2021). Therefore, detailed data on afferent projections of the prostriata are only available in rats and mice (Chen et al., 2021; Hu et al., 2020).…”