title: Resting state fMRI in Alzheimer's disease: beyond the default mode network.
abstract: Using resting state (RS) functional magnetic resonance imaging (fMRI), the connectivity patterns of the default mode (DMN), frontoparietal, executive, and salience networks were explored in 13 Alzheimer's disease (AD) patients, 12 amnestic mild cognitive impairment (aMCI) patients, and 13 healthy controls. Compared with controls and aMCI, AD was associated with opposing connectivity effects in the DMN (decreased) and frontal networks (enhanced). The only RS abnormality found in aMCI patients compared with controls was a precuneus connectivity reduction in the DMN. RS fMRI group differences were only partly related to gray matter atrophy. In AD patients, the mean executive network connectivity was positively associated with frontal-executive and language neuropsychological scores. These results suggest that AD is associated with an alteration of large-scale functional brain networks, which extends well beyond the DMN. In AD, the limited resources of the DMN may be paralleled, in an attempt to maintain cognitive efficiency, by an increased prefrontal connectivity. A medial parietal RS fMRI signal change seems to be present since the early phase of AD.
authors.affiliation: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Agosta
authors.forename: Michela
authors.initials: M
authors.lastname: Pievani
authors.forename: Cristina
authors.initials: C
authors.lastname: Geroldi
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Copetti
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Frisoni
authors.forename: Massimo
authors.initials: M
authors.lastname: Filippi
mesh_terms: D000200:Action Potentials; D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D012146:Rest