Poster E99, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
Distinct spatiotemporal patterns of resting state neuronal synchrony in Alzheimer’s disease spectrum
Kamalini G Ranasinghe1, Leighton B Hinkley2, Alexander J Beagle1, Alice La1, Danielle Mizuiri2, Susanne Honma2, John F Houde3, Bruce L Miller1, Keith A Vossel1,4, Srikantan Nagarajan2; 1University of California San Francisco, Memory and Aging Center, 2University of California San Francisco, Biomagnetic Imaging Laboratory, 3University of California San Francisco, Speech Neuroscience Laboratory, 4Gladstone Institute of Neurological Disease
Alzheimer’s disease (AD) is characterized by progressive loss of memory and other cognitive functions. There are three main phenotypic clinical presentations of AD including amnestic/dysexecutive (Amn/dys), logopenic variant primary progressive aphasia (lvPPA), and posterior cortical atrophy (PCA). Structural and functional neuroimaging studies have implicated unique anatomic involvements in each variant. Resting-state brain oscillations represent coordinated activity in large groups of neurons and hence provide a tool to quantify spontaneous neuronal activity and functional network integrity of neural circuits. We hypothesized that resting state brain oscillations will show unique deficits in each variant of AD. We examined Amn/dys (n=30), lvPPA (n=15) and PCA (n=13) patients using magnetoencephalogrpahy, compared to a control group (n=20). Each patient underwent a complete clinical evaluation including a battery of neuropsychological tests. We examined the global resting-state functional connectivity patterns within delta-theta (2-8Hz), alpha (8-12Hz), and beta (12-30Hz) frequency oscillations, in each patient group, compared to age-matched controls. We found that each AD variant shows distinct anatomic patterns of reduced functional connectivity within alpha and beta band oscillations. In contrast, within delta-theta band, all three variants showed spatially nonspecific patterns of hypersynchorny. The current results demonstrate the first evidence of direct neuronal activity patterns recorded in a comprehensive evaluation of the three AD variants. Unique spatial distributions of hyposynchony within alpha and beta bands, and distinctive temporal patterns of increased and decreased synchronizations indicate that network failure in each syndrome is driven by diverse cellular and molecular mechanisms.
Topic Area: METHODS: Neuroimaging