MAPT and Alzheimer disease: We found an increase in Syk activation in DNs surrounding Aβ deposits as well as in neurons displaying an accumulation of phosphorylated Tau at Y18 and elevated levels of MC1 pathogenic tau conformers in AD brain sections whereas only weak immunoreactivity for pSyk was observed in brain sections from a non-demented control (Figs. 15, 16 and 17).