Amyloid beta–positive subjects exhibit longitudinal network-specific reductions in spontaneous brain activity

• Published in: Neurobiology of aging Vol. 74; pp. 191 - 201
• Main Authors: Avants, Brian B., Hutchison, R. Matthew, Mikulskis, Alvydas, Salinas-Valenzuela, Cristian, Hargreaves, Richard, Beaver, John, Chiao, Ping
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2019
• Subjects: Alzheimer's disease; Amyloid beta; Fluorodeoxyglucose positron emission tomography; Reference region spontaneous brain activity; Resting-state functional magnetic resonance imaging; Amyloid beta; Reference region spontaneous brain activity; Resting-state functional magnetic resonance imaging; Alzheimer's disease; Fluorodeoxyglucose positron emission tomography
• ISSN: 0197-4580; 1558-1497; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2018.10.002

Amyloid beta (Aβ) deposition and cognitive decline are key features of Alzheimer's disease. The relationship between Aβ status and changes in neuronal function over time, however, remains unclear. We evaluated the effect of baseline Aβ status on reference region spontaneous brain activity (SBA-rr) using resting-state functional magnetic resonance imaging and fluorodeoxyglucose positron emission tomography in patients with mild cognitive impairment. Patients (N = 62, [43 Aβ-positive]) from the Alzheimer's Disease Neuroimaging Initiative were divided into Aβ-positive and Aβ-negative groups via prespecified cerebrospinal fluid Aβ42 or 18F-florbetapir positron emission tomography standardized uptake value ratio cutoffs measured at baseline. We analyzed interaction of biomarker-confirmed Aβ status with SBA-rr change over a 2-year period using mixed-effects modeling. SBA-rr differences between Aβ-positive and Aβ-negative subjects increased significantly over time within subsystems of the default and visual networks. Changes exhibit an interaction with memory performance over time but were independent of glucose metabolism. Results reinforce the value of resting-state functional magnetic resonance imaging in evaluating Alzheimer'’s disease progression and suggest spontaneous neuronal activity changes are concomitant with cognitive decline. •Longitudinal spontaneous brain activity differences between Aβ-positive and -negative subjects increased significantly over time within subsystems of the default and visual networks.•Changes in longitudinal spontaneous brain activity were independent of glucose metabolism.•Analysis of longitudinal spontaneous brain activity highlights the potential use of rs-fMRI in evaluating AD progression.