Spatial Navigation Impairment Is Associated with Alterations in Subcortical Intrinsic Activity in Mild Cognitive Impairment: A Resting-State fMRI Study.

Zhao Qing,Bing Zhang,Zuzana Nedelska,Bin Zhu,Wenbo Wu,Queenie Chan,Weibo Chen,Weiping Li,Jakub Hort,Fangfang Wang,Hui Zhao,Renyuan Liu,Yun Xu

doi:10.1155/2017/6364314

Abstract

Impairment of spatial navigation (SN) skills is one of the features of the Alzheimer's disease (AD) already at the stage of mild cognitive impairment (MCI). We used a computer-based battery of spatial navigation tests to measure the SN performance in 22 MCI patients as well as 21 normal controls (NC). In order to evaluate intrinsic activity in the subcortical regions that may play a role in SN, we measured ALFF, fALFF, and ReHo derived within 14 subcortical regions. We observed reductions of intrinsic activity in MCI patients. We also demonstrated that the MCI versus NC group difference can modulate activity-behavior relationship, that is, the correlation slopes between ReHo and allocentric SN task total errors were significantly different between NC and MCI groups in the right hippocampus (interaction F = 4.44, p = 0.05), pallidum (F = 8.97, p = 0.005), and thalamus (F = 5.95, p = 0.02), which were negative in NC (right hippocampus, r = −0.49; right pallidum, r = −0.50; right thalamus, r = −0.45; all p < 0.05) but absent in MCI (right hippocampus, r = 0.21; right pallidum, r = 0.32; right thalamus r = 0.28; all p > 0.2). These findings may provide a novel insight of the brain mechanism associated with SN impairment in MCI and indicated a stage specificity of brain-behavior correlation in dementia. This trial is registered with ChiCTR-BRC-17011316.

Highlights

Deterioration of spatial navigation (SN) skills is often present early in the course of Alzheimer’s disease (AD), at least at the stage of mild cognitive impairment (MCI), and has a serious impact on the quality of patients’ daily life [1,2,3,4,5]
We evaluated whether the correlation between SN performance and resting-state functional magnetic resonance imaging (rs-fMRI) measures has a statistical difference between MCI and normal controls (NC)
After controlling for age, gender, education, and scanner type, only the regional homogeneity (ReHo) was significantly lower in the MCI group in the right thalamus (t = 2 24, p = 0 03), right hippocampus (t = 2 75, p = 0 01), right pallidum (t = 2 13, p = 0 04), and right amygdala (t = 2 98, p = 0 01) compared to the NC group (Figure 2)

Summary

Introduction

Deterioration of spatial navigation (SN) skills is often present early in the course of Alzheimer’s disease (AD), at least at the stage of mild cognitive impairment (MCI), and has a serious impact on the quality of patients’ daily life [1,2,3,4,5]. Based on an extensive work in animals and humans, two basic strategies of SN have been widely recognized: egocentric (self-based) and allocentric (world-based) [2, 6], and their association with brain regions were investigated [7,8,9]. The subcortical regions may play a critical role in the SN [3, 6, 10, 11]. Alterations in the intrinsic brain activity have been associated with cognitive impairment in both AD and MCI [17,18,19]. The aberrant intrinsic activities in the subcortical regions in MCI and AD patients have been previously reported [20,21,22]. Our primary objective was to assess whether the subcortical intrinsic activity is associated with the SN impairment in patients with MCI. We hypothesized that the SN impairment would be related to abnormal intrinsic brain activity within subcortical areas

Material and Methods

Results

Discussion

Conclusion