title: Distinct functional activity of the precuneus and posterior cingulate cortex during encoding in the preclinical stage of Alzheimer's disease.
abstract: In this study functional magnetic resonance imaging (fMRI) is used to investigate the functional brain activation pattern in the preclinical stage of AD (pre-AD) subjects during a visual encoding memory task. Thirty subjects, eleven in the pre-AD stage, with decreased cerebrospinal fluid levels of Aβ42 (<500 pg/ml), and 19 controls with normal Aβ42 levels (CTR) were included. fMRI was acquired during a visual encoding task. Data were analyzed through an Independent Component Analysis (ICA) and region-of-interest-based univariate analysis of task-related BOLD signal change. From the ICA decomposition, we identified the main task-related component, which included the activation of visual associative areas and prefrontal executive regions, and the deactivation of the default-mode network. The activation was positively correlated with task performance in the CTR group (p < 0.0054). Within this pattern, subjects in the pre-AD stage had significantly greater activation of the precuneus and posterior cingulate cortex during encoding. Subjects in the pre-AD stage present distinct functional neural activity before the appearance of clinical symptomatology. These findings may represent that subtle changes in functional brain activity precede clinical and cognitive symptoms in the AD continuum. Present findings provide evidence suggesting that fMRI may be a suitable biomarker of preclinical AD.
authors.affiliation: Alzheimer's Disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clínic, Barcelona, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Rami
authors.forename: Roser
authors.initials: R
authors.lastname: Sala-Llonch
authors.forename: Cristina
authors.initials: C
authors.lastname: Solé-Padullés
authors.forename: Juan
authors.initials: J
authors.lastname: Fortea
authors.forename: Jaume
authors.initials: J
authors.lastname: Olives
authors.forename: Albert
authors.initials: A
authors.lastname: Lladó
authors.forename: Cleofe
authors.initials: C
authors.lastname: Peña-Gómez
authors.forename: Mircea
authors.initials: M
authors.lastname: Balasa
authors.forename: Bea
authors.initials: B
authors.lastname: Bosch
authors.forename: Anna
authors.initials: A
authors.lastname: Antonell
authors.forename: Raquel
authors.initials: R
authors.lastname: Sanchez-Valle
authors.forename: David
authors.initials: D
authors.lastname: Bartrés-Faz
authors.forename: Jose L
authors.initials: JL
authors.lastname: Molinuevo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000175:diagnosis* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid; D042241:Early Diagnosis; D005260:Female; D006179:Gyrus Cinguli / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins