Apathy and intrinsic functional connectivity networks in amnestic mild cognitive impairment

BACKGROUND Although several prior works reported that apathy is associated with conversion to Alzheimer's disease in individuals with amnestic mild cognitive impairment (aMCI), effects of apathy on the functional connectivity (FC) of the brain remain unclear. In this study, we assessed the pattern of association between apathy and default mode network (DMN), salience network and central executive network (CEN) in aMCI subjects. METHODS Fifty subjects with aMCI and 50 controls (CONs) participated in this study. They underwent clinical assessments and magnetic resonance imaging for the structural and resting-state scan. We explored the patterns of association between apathy inventory (IA) total score and the whole-brain voxel-wise FCs of the DMN, salience network and CEN in aMCI subjects. RESULTS We observed that the FCs of the DMN were less and those of CEN were more in the aMCI group than the CON group. Total IA score was negatively correlated with FCs of the anterior cingulate within the DMN, and positively correlated with FCs of the middle frontal, inferior frontal, and supramarginal gyrus within the CEN in the aMCI group. CONCLUSION Our findings suggest that distinctive patterns of association between apathy and FCs in the DMN and CEN in the aMCI group might reflect the putative role of functional network change in the development of apathy in aMCI.