Lower synaptic density and higher neurofibrillary tau are associated with worse cognitive performance

Synaptic loss is a major feature of symptomatic Alzheimer’s disease (AD). PET radioligands for synaptic vesicle glycoprotein 2A (SV2A) provide an index for synaptic density in the brain. While development of these tracers is a major advance for the field of AD, little is yet known about regional synapse loss in AD or the extent to which synapse loss accounts for cognitive dysfunction in vivo. Here we tested whether regional synaptic density measured with [11C]UCB‐J is associated with cognition. Secondarily, we examined the association between tau, measured using [18F]MK‐6420 PET, and cognitive dysfunction.