Altered organization of the visual cortex in FHONDA syndrome

TY - JOUR

T1 - Altered organization of the visual cortex in FHONDA syndrome

AU - Ahmadi, Khazar

AU - Fracasso, A.

AU - van Dijk, Jelle A

AU - Kruijt, Charlotte

AU - van Genderen, Maria M

AU - Dumoulin, Serge O

AU - Hoffmann, Michael B

N1 - Copyright © 2018. Published by Elsevier Inc.

PY - 2019

Y1 - 2019

N2 - A fundamental scheme in the organization of the early visual cortex is the retinotopic representation of the contralateral visual hemifield on each hemisphere. We determined the cortical organization in a novel congenital visual pathway disorder, FHONDA-syndrome, where the axons from the temporal retina abnormally cross to the contralateral hemisphere. Using ultra-high field fMRI at 7 T, the population receptive field (pRF) properties of the primary visual cortex were modeled for two affected individuals and two controls. The cortical activation in FHONDA was confined to the hemisphere contralateral to the stimulated eye. Each cortical location was found to contain a pRF in each visual hemifeld and opposing hemifields were represented as retinotopic cortical overlays of mirror-symmetrical locations across the vertical meridian. Since, the enhanced crossing of the retinal fibers at the optic chiasm observed in FHONDA has been previously assumed to be exclusive to the pigment-deficiency in albinism, our direct evidence of abnormal mapping in FHONDA highlights the independence of pigmentation and development of the visual cortex. These findings thus provide fundamental insights into the developmental mechanisms of the human visual system and underline the general relevance of the interplay of subcortical stability and cortical plasticity.

AB - A fundamental scheme in the organization of the early visual cortex is the retinotopic representation of the contralateral visual hemifield on each hemisphere. We determined the cortical organization in a novel congenital visual pathway disorder, FHONDA-syndrome, where the axons from the temporal retina abnormally cross to the contralateral hemisphere. Using ultra-high field fMRI at 7 T, the population receptive field (pRF) properties of the primary visual cortex were modeled for two affected individuals and two controls. The cortical activation in FHONDA was confined to the hemisphere contralateral to the stimulated eye. Each cortical location was found to contain a pRF in each visual hemifeld and opposing hemifields were represented as retinotopic cortical overlays of mirror-symmetrical locations across the vertical meridian. Since, the enhanced crossing of the retinal fibers at the optic chiasm observed in FHONDA has been previously assumed to be exclusive to the pigment-deficiency in albinism, our direct evidence of abnormal mapping in FHONDA highlights the independence of pigmentation and development of the visual cortex. These findings thus provide fundamental insights into the developmental mechanisms of the human visual system and underline the general relevance of the interplay of subcortical stability and cortical plasticity.

KW - Journal Article

KW - Review

U2 - 10.1016/j.neuroimage.2018.02.053

DO - 10.1016/j.neuroimage.2018.02.053

M3 - Article

C2 - 29524626

SN - 1053-8119

VL - 190

SP - 224

EP - 231

JO - NeuroImage

JF - NeuroImage

ER -