MAPT and Mental deterioration: However, though NFTs correlate better with cognitive decline and neuronal loss (Braak and Braak, 1991b; Arriagada et al., 1992; Gomez-Isla et al., 1997; Giannakopoulos et al., 2003) than amyloid deposits, they do not seem to be the most toxic tau aggregates in disease, with many studies supporting the hypothesis that soluble oligomers drive tau toxicity (Maeda et al., 2006, 2007; Patterson et al., 2011; Lasagna-Reeves et al., 2012b).