Altered Functional Connectivity of Resting-State Networks and the Correlation with Clinical Characteristics in Intermittent Exotropia: A Resting-state Magnetic Resonance Imaging Study

Background: The pathogenesis of intermittent exotropia (IXT) remains unclear. The study aims to investigate alterations of resting-state networks (RSNs) in IXT patients using resting-state functional magnetic resonance imaging (rs-fMRI) data to explore the potential neural mechanisms. Methods: 26 IXT patients and 22 age-, sex-, handedness-, and education-matched healthy controls (HCs) underwent fMRI scanning and ophthalmological examinations. Brain areas with significant functional connectivity (FC) differences between the IXT and HC groups were selected as regions of interest (ROI) and mean z-scores were calculated to control for individual differences. Results: Compared with HCs, IXT patients exhibited altered FC in various brain regions within RSNs involved in binocular fusion, stereopsis, ocular movement, emotional processes and social cognition, including the default mode network (DMN), the dorsal attention network (DAN), the visual network (VN), the sensorimotor network (SMN), the executive control network (ECN), the frontoparietal network (FPN) and the auditory network (AN). The degree of exodeviation was positively correlated with FC value of left middle occipital gyrus (MOG) within the VN. Correspondingly, we found a negative correlation between the degree of exodeviation and the FC value of left angular gyrus (AG) within FPN(P<0.05). The FNC analysis between different RSNs also provides evidence on visual-motor cortical plasticity. Conclusions: IXT patients showed widespread changes of brain activity within RSNs related to binocular fusion, stereopsis, oculomotor control, emotional processes, and social cognition. These findings extend our current understanding of the neuropathological mechanisms of IXT. Trial registration: Beginning date of the trial: 2021-09-01 Date of registration:2021-07-18 Trial registration number: ChiCTR 2100048852 Tegistration site: http://www.chictr.org.cn/index.aspx