Altered regional homogeneity in patients with late monocular blindness: a resting-state functional MRI study

Abstract

Many previous studies have demonstrated that the blindness patients have has functional and anatomical abnormalities in the visual and other vision-related cortex. However, changes in the brain function in late monocular blindness (MB) at rest are largely unknown. In this study, we investigated the underlying regional homogeneity (ReHo) of brain-activity abnormalities in patients with late MB and their relationship with clinical features. A total of 32 patients with MB (25 male and seven female) and 32 healthy controls (HCs) (25 male and seven female) closely matched in age, sex, and education underwent resting-state functional MRI scans. The ReHo method was used to assess local features of spontaneous brain activities. Patients with MB were distinguishable from HCs using the receiver operating characteristic curve. The relationship between the mean ReHo in brain regions and the behavioral performance was calculated using correlation analysis. Compared with HCs, patients with MB showed significantly decreased ReHo values in the right rectal gyrus, right cuneus, right anterior cingulate, and right lateral occipital cortex and increased ReHo values in the right inferior temporal gyrus, right frontal middle orbital, left posterior cingulate/precuneus, and left middle frontal gyrus. However, there was no significant relationship between the different mean ReHo values in the brain regions and the clinical features. Late MB involves abnormalities of the visual cortex and other vision-related brain regions, which may reflect brain dysfunction in these regions.

Fig. 1

Spontaneous brain activity in the monocular blindness and healthy control groups. Significant activity differences were observed in the right rectal gyrus, right cuneus, right anterior cingulate, right lateral occipital cortex, right inferior temporal gyrus, right frontal middle orbital, left posterior cingulate/precuneus, and left middle frontal gyrus. Black denotes higher regional homogeneity values. [P<0.01 for multiple comparisons using Gaussian random field theory (z>2.3, P<0.01, cluster>40 voxels, AlphaSim corrected)].

Fig. 2

The mean values of altered ReHo values between the MB and HC groups. HC, healthy control; MB, monocular blindness; ReHo, regional homogeneity.

Fig. 3

ROC curve analysis of the mean regional homogeneity values for altered brain regions. The AUCs were 0.771 (P<0.001; 95% CI: 0.657–0.886) for the RRG, 0.715 (P=0.003; 95% CI: 0.589–0.840) for the RC, 0.828 (P<0.001; 95% CI: 0.729–0.927) for the RAC, and 0.756 (P<0.001; 95% CI: 0.639–0.873) for the RLOC (MBs<HCs). (a) The AUCs were 0.778 (P<0.001; 95% CI: 0.667-0.889) for the RITG, 0.795 (P<0.001; 95% CI: 0.687–0.903) for the RFMO, 0.793 (P<0.001; 95% CI: 0.685–0.901) for the LPC/P, and 0.782 (P<0.001; 95% CI: 0.668–0.897) for the LMFG (MBs>HCs) (b). AUC, area under the curve; CI, confidence interval; HC, healthy control; LMFG, left middle frontal gyrus; LPC/P, left posterior cingulate/precuneus; MB, monocular blindness; RAC, right anterior cingulate; RC, right cuneus; RFMO, right frontal middle orbital; RITG, right inferior temporal gyrus; RLOC, right lateral occipital cortex; ROC, receiver operating characteristic; RRG, right rectal gyrus.