Altered Spontaneous Brain Activity of Children with Unilateral Amblyopia: A Resting State fMRI Study.

Peishan Dai,Manyi Xiao,Jinlong Zhang,Ying Wu,Xin Wei,Beiji Zou,Jing Wu,Zailiang Chen

doi:10.1155/2019/3681430

Abstract

Objective This study is aimed at investigating differences in local brain activity and functional connectivity (FC) between children with unilateral amblyopia and healthy controls (HCs) by using resting state functional magnetic resonance imaging (rs-fMRI). Methods Local activity and FC analysis methods were used to explore the altered spontaneous brain activity of children with unilateral amblyopia. Local brain function analysis methods included the amplitude of low-frequency fluctuation (ALFF). FC analysis methods consisted of the FC between the primary visual cortex (PVC-FC) and other brain regions and the FC network between regions of interest (ROIs-FC) selected by independent component analysis. Results The ALFF in the bilateral frontal, temporal, and occipital lobes in the amblyopia group was lower than that in the HCs. The weakened PVC-FC was mainly concentrated in the frontal lobe and the angular gyrus. The ROIs-FC between the default mode network, salience network, and primary visual cortex network (PVCN) were significantly reduced, whereas the ROIs-FC between the PVCN and the high-level visual cortex network were significantly increased in amblyopia. Conclusions Unilateral amblyopia may reduce local brain activity and FC in the dorsal and ventral visual pathways and affect the top-down attentional control. Amblyopia may also alter FC between brain functional networks. These findings may help understand the pathological mechanisms of children with amblyopia.

Highlights

Amblyopia is a neurodevelopmental disorder of the visual cortex characterized by visual deficiency in an eye that is otherwise physically normal or by a deficiency that is out of proportion with the structural abnormalities of the eyes [1,2,3], thereby affecting 2%–4% of the general population [4]
amplitude of low-frequency fluctuation (ALFF) analysis showed that the brain regions with lower ALFF values in the amblyopia group than those in the healthy controls (HCs) were distributed in the bilateral brain, including frontal, temporal, and occipital lobes
The brain regions with higher ALFF values in the amblyopia group than those in HCs were distributed in the right fusiform gyrus, the right caudate nucleus, and the right superior parietal gyrus

Summary

Introduction

Amblyopia is a neurodevelopmental disorder of the visual cortex characterized by visual deficiency in an eye that is otherwise physically normal or by a deficiency that is out of proportion with the structural abnormalities of the eyes [1,2,3], thereby affecting 2%–4% of the general population [4]. The peak of brain plasticity is in early childhood [7], so the brain functional mechanism of amblyopia in children should be investigated to administer treatments timely and accurately. Functional magnetic resonance imaging (fMRI) can be applied to investigate brain activity noninvasively; as such, fMRI is widely used to reveal neuropathological mechanisms in amblyopia [8, 9]. Amblyopia is considered a visual cortex but not a retinal dysfunction [10]. For this reason, brain areas on the vision pathway have been widely explored.

Methods

Results

Conclusion