MAPT and tauopathy: If tau mediates frequency-dependent release of glutamate, then this represents an important potential pathway of disease progression, because prior studies have demonstrated a glutamate-mediated exocytosis of tau as a potential mechanism for the trans-synaptic spread of tau pathology (Liu et al., 2012; Pooler et al., 2013; Yamada et al., 2014), and neuronal hyperexcitability represents one potential source for the pathogenesis of tauopathies (see Toniolo et al., 2020 for review).