Triple visual hemifield maps in a case of optic chiasm hypoplasia

TY - JOUR

T1 - Triple visual hemifield maps in a case of optic chiasm hypoplasia

AU - Ahmadi, Khazar

AU - Fracasso, Alessio

AU - Puzniak, Robert J

AU - Gouws, Andre D

AU - Yakupov, Renat

AU - Speck, Oliver

AU - Kaufmann, Joern

AU - Pestilli, Franco

AU - Dumoulin, Serge O

AU - Morland, Antony B

AU - Hoffmann, Michael B

N1 - Copyright © 2020. Published by Elsevier Inc.

PY - 2020/4/7

Y1 - 2020/4/7

N2 - In humans, each hemisphere comprises an overlay of two visuotopic maps of the contralateral visual field, one from each eye. Is the capacity of the visual cortex limited to these two maps or are plastic mechanisms available to host more maps? We determined the cortical organization of the visual field maps in a rare individual with chiasma hypoplasia, where visual cortex plasticity is challenged to accommodate three hemifield maps. Using high-resolution fMRI at 7T and diffusion-weighted MRI at 3T, we found three hemiretinal inputs, instead of the normal two, to converge onto the left hemisphere. fMRI-based population receptive field mapping of the left V1-V3 at 3T revealed three superimposed hemifield representations in the left visual cortex, i.e. two representations of opposing visual hemifields from the left eye and one right hemifield representation from the right eye. We conclude that developmental plasticity including the re-wiring of local intra- and cortico-cortical connections is pivotal to support the coexistence and functioning of three hemifield maps within one hemisphere.

AB - In humans, each hemisphere comprises an overlay of two visuotopic maps of the contralateral visual field, one from each eye. Is the capacity of the visual cortex limited to these two maps or are plastic mechanisms available to host more maps? We determined the cortical organization of the visual field maps in a rare individual with chiasma hypoplasia, where visual cortex plasticity is challenged to accommodate three hemifield maps. Using high-resolution fMRI at 7T and diffusion-weighted MRI at 3T, we found three hemiretinal inputs, instead of the normal two, to converge onto the left hemisphere. fMRI-based population receptive field mapping of the left V1-V3 at 3T revealed three superimposed hemifield representations in the left visual cortex, i.e. two representations of opposing visual hemifields from the left eye and one right hemifield representation from the right eye. We conclude that developmental plasticity including the re-wiring of local intra- and cortico-cortical connections is pivotal to support the coexistence and functioning of three hemifield maps within one hemisphere.

U2 - 10.1016/j.neuroimage.2020.116822

DO - 10.1016/j.neuroimage.2020.116822

M3 - Article

C2 - 32276070

SN - 1053-8119

VL - 215

SP - 116822

JO - NeuroImage

JF - NeuroImage

ER -