MAPT and Cognitive impairment: Basal levels of serine phosphorylated IRS-1 were negatively correlated with measures of working- and episodic memory performance (previously collected from this cohort) even after controlling for Aβ plaques and tau neurofibrillary tangles, which suggests that IR/IGF-1 resistance in the brain may encourage cognitive impairments independently of plaques and tangles.