Altered self-referential network in resting-state amnestic type mild cognitive impairment

Introduction: Impaired capacity for self-reference has been observed in amnestic mild cognitive impairment (aMCI) subjects who are thought to be the likely to develop into clinical Alzheimer's disease (AD). The altered pattern of self-referencing network (SRN) is not yet well understood in aMCI subjects particularly in resting state, and little is known about the relationship between SRN and other resting-state networks in aMCI subjects. Methods: The study was designed to administer longitudinal resting-state functional magnetic resonance imaging (fMRI) scanning to 26 aMCI subjects and 18 matched healthy controls. Independent component analysis was used to separate SRN, and a further crosscorrelation approach was recruited to explore the relationship between SRN and other resting-state networks. Results: Compared to controls, selective changes of SRN regarding to the increased functional connectivity between ventromedial prefrontal cortex/medial orbital prefrontal cortex/gyrus rectus and the mean time series of SRN at baseline in aMCI, while these functional connections were associated with more extent of longitudinal diminish after follow up in the same subjects. In addition, greater decreased connectivity relationship between SRN and default mode network was observed in aMCI subjects. Conclusions: Altered patterns of resting-state SRN were firstly explored in aMCI subjects, and it could help guide subsequent investigations designed to specify the precise functional implications of SRN in the progression of aMCI. Crown Copyright (C) 2011 Published by Elsevier Srl. All rights reserved.