Chronic dosing of methylene blue enhances neuronal survival. (A) Parenchymal drug concentrations correlated significantly with memory retention in the probe trial of MWM p = 0.016, Pearson r = 0.766, r2 = 0.587. (B) Tau levels inversely correlate significantly with parenchymal drug concentration, p < 0.05, Pearson r = -0.6724, r2 = 0.452. (C) Number of neurons counted in five regions as a percentage of sacc treated rTg4510 (MB treated rTg4510 n = 8, sacc treated rTg4510 n = 10) (DG stands for dentate gyrus, CX stands for cortex and STR stands for striatum). (D) Number of neurons does not correlate significantly with time spent in the target quadrant.