Venue: Centre Broca
Hiromasa Takemura
National Institute for Physiological Sciences
Okazaki, Japan
https://www.nips.ac.jp/scbm/en/member/2021/08/HiromasaTakemura.html
https://scholar.google.com/citations?user=ac6b5c8AAAAJ&hl=en
Invited by Michel Thiebaut de Schotten
Title
Visual field maps and white matter tracts in the human visual system
Abstract
Over the last several decades, system neuroscience has made substantial progress in understanding brain functions by measuring response properties of individual brain regions and their relation to behavior. However, it is not yet fully understood how such brain functions are related to the structural properties of the nervous system. To address unresolved question on structure-function relationship in the brain, one needs to understand how functional organization of the brain is related to the neuroanatomy. The visual system is an ideal system to address such question since functional organization principle of visual areas, such as visual field maps, and anatomical connections between areas are relatively understood. In this talk, I will describe recent studies investigating the relationship between functional organization of the visual areas and neuroanatomy of the visual system. First, I will describe a recent study (Miyata et al., 2022) investigating a relationship between the size of the human primary visual cortex (V1) and the optic tract by analyzing fMRI and diffusion-weighted MRI (dMRI) in the Human Connective Project 7T Retinotopy dataset (Benson et al., 2018), based on hypothesis from a previous post-mortem study (Andrews et al., 1997). Second, I will describe studies investigating the relationship between human extrastriate visual field maps (V3A/B and hV4) and the Vertical Occipital Fasciculus (VOF), which is a white matter tract connecting dorsal and ventral visual streams (Takemura et al., 2016). The analysis combining fMRI and dMRI suggests that the VOF is an important pathway for integration of upper and lower visual field information in the human visual system. In addition, I will discuss that such finding can be extended into non-human primate visual system (Takemura et al., 2017; 2020). Finally, I will briefly describe other recent projects in the lab, such as a parcellation of the visual thalamus using quantitative MRI (Oishi et al., 2023) and comparative diffusion MRI on visual white matter pathways.