ALTERED FUNCTIONAL CONNECTIVITY OF THE BASAL NUCLEUS OF MEYNERT IN MILD COGNITIVE IMPAIRMENT: A RESTING-STATE FMRI STUDY

Abstract

Cholinergic dysfunction plays an important role in mild cognitive impairment (MCI). The basal nucleus of Meynert (BNM) provides the main source of cortical cholinergic innervation. Previous studies have characterized structural changes of the cholinergic basal forebrain in individuals at risk of developing Alzheimer's disease. However, whether and how functional connectivity of the BNM (BNM-FC) is altered in MCI remains unknown. One-hundred-and-eleven MCI patients and one hundred and seven HCs underwent resting-state functional magnetic resonance imaging (rs-fMRI). Imaging data were processed with Statistical Parametric Mapping. BNM-FC was examined via correlation in low frequency fMRI signal fluctuations between the BNM and all other brain voxels. Group difference was tested by covariance analysis to control for age, gender, and years of education. Pearson regression was conducted to evaluate the relationship between the BNM-FC and clinical assessments. Compared with HCs, MCI group showed decreased BNM-FC in the right anterior cingulate cortex (ACC), right putamen, as well as left insula and dorsal striatum, including claustrum, putamen/pallidum and caudate. Further, greater decreases in BNM-FC to these regions were associated with more severe impairment in immediate and delayed recall in MCI patients.