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Neuroimage. 2017 Sep 21. pii: S1053-8119(17)30793-0. doi: 10.1016/j.neuroimage.2017.09.045. [Epub ahead of print]

Two cortical deficits underlie amblyopia: A multifocal fMRI analysis.

Author information

1
McGill Vision Research, Dept. Ophthalmology, McGill University, The Research Institute of the McGill University Health Centre, Montreal, PQ, Canada. Electronic address: reza.farivar@mcgill.ca.
2
School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, PR China. Electronic address: zhoujw@mail.eye.ac.cn.
3
CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, PR China.
4
Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, PR China.
5
McGill Vision Research, Dept. Ophthalmology, McGill University, The Research Institute of the McGill University Health Centre, Montreal, PQ, Canada.

Abstract

Amblyopia is a relatively common (incidence 3%) developmental disorder in which there is loss of vision as a consequence of a disruption to normal visual development. Although the deficit is monocular and known to be of cortical origin, the nature of the processing deficit is controversial. Human behavioral studies have identified two main deficits - a loss of contrast sensitivity and perceived spatial distortions. Here we use a multifocal fMRI approach to ascertain, in a group of anisometropic amblyopes, whether these two deficits have a single common cause or whether they are the result of two underlying independent cortical disorders. We found that fMRI magnitudes were attenuated in amblyopic eye stimulation, and that there was poor fidelity for co-localization of the activity clusters between the amblyopic and fellow-fixing eye stimulation. These effects varied across eccentricities and correlate with the degree of amblyopia but not with one another, suggesting two independent cortical deficits: a reduced responsiveness as well as reduced fidelity of spatial representation. These deficits are independent of eccentricity within the central field and consistent across early cortical visual areas.

KEYWORDS:

Amblyopia; BOLD; Distortion; Multifocal; Visual acuity

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