TY - JOUR T1 - <em>In-vivo</em> tau pathology is associated with synaptic loss and altered synaptic function JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 43 LP - 43 VL - 62 IS - supplement 1 AU - Emma Coomans AU - Deborah Schoonhoven AU - Hayel Tuncel AU - Sander Verfaillie AU - Emma Wolters AU - Ronald Boellaard AU - Rik Ossenkoppele AU - Anouk den Braber AU - Wiep Scheper AU - Patrick Schober AU - Steven Sweeney AU - J Michael Ryan AU - Robert Schuit AU - Albert Windhorst AU - Frederik Barkhof AU - Philip Scheltens AU - Sandeep Golla AU - Arjan Hillebrand AU - Alida Gouw AU - Bart van Berckel Y1 - 2021/05/01 UR - http://jnm.snmjournals.org/content/62/supplement_1/43.abstract N2 - 43Objectives: The mechanism of synaptic loss in Alzheimer’s disease is poorly understood and may be associated with tau pathology. In this combined positron emission tomography (PET) and magnetoencephalography (MEG) study, we aimed to investigate spatial associations between regional tau pathology ([18F]flortaucipir PET), synaptic density (synaptic vesicle 2A [11C]UCB-J PET) and synaptic function (MEG) in Alzheimer’s disease. Methods: Seven amyloid-positive Alzheimer’s disease subjects from the Amsterdam Dementia Cohort underwent dynamic 130-minutes [18F]flortaucipir PET, dynamic 60-minutes [11C]UCB-J PET with arterial sampling and 2x5-minutes resting-state MEG measurement. [18F]flortaucipir and [11C]UCB-J specific binding (binding potential, BPND) and MEG spectral measures (relative delta, theta and alpha power, broadband power and peak frequency) were assessed in cortical brain regions of interest. Associations between regional [18F]flortaucipir BPND, [11C]UCB-J PET BPND and MEG spectral measures were assessed using Spearman correlations and generalized estimating equation models. Results: Across subjects, higher regional [18F]flortaucipir uptake was associated with lower [11C]UCB-J uptake. Within subjects, the association between [11C]UCB-J and [18F]flortaucipir depended on within-subject neocortical tau load; negative associations were observed when neocortical tau load was high, gradually changing into opposite patterns with decreasing neocortical tau burden. Both higher [18F]flortaucipir and lower [11C]UCB-J uptake were associated with altered synaptic function, indicative of slowing of oscillatory activity, most pronounced in the occipital lobe. Conclusions: These results indicate that in Alzheimer’s disease tau pathology is closely associated with reduced synaptic density and synaptic dysfunction. ER -