Altered organization of the visual cortex in FHONDA syndrome

Ahmadi, K., Fracasso, A. , van Dijk, J. A., Kruijt, C., van Genderen, M., Dumoulin, S. O. and Hoffmann, M. B. (2019) Altered organization of the visual cortex in FHONDA syndrome. NeuroImage, 190, pp. 224-231. (doi:10.1016/j.neuroimage.2018.02.053) (PMID:29524626)

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Abstract

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.

Item Type:Articles
Additional Information:This work was supported by European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement (No 641805) to M.B.H and S.O.D. and the German Research Foundation (DFG: HO2002/10-2) to M.B.H.
Keywords:FHONDA, plasticity, visual cortex, fMRI, pRF.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fracasso, Dr Alessio
Authors: Ahmadi, K., Fracasso, A., van Dijk, J. A., Kruijt, C., van Genderen, M., Dumoulin, S. O., and Hoffmann, M. B.
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:NeuroImage
Publisher:Elsevier
ISSN:1053-8119
ISSN (Online):1095-9572
Published Online:08 March 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in NeuroImage 190: 224-231
Publisher Policy:Reproduced under a Creative Commons License

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