MAPT and Alzheimer disease: Finally, there were significantly more tau inclusions per plaque with increased plaque size and age in TgF344-AD rats (9-month Y = 0.003 X + 4.52, 12-month Y = 0.004 X + 6.15, 15-month Y = 0.009 X + 2.57; with significant differences in slope, F(2,264) = 63.23, P < 0.0001, Fig. 3g).