GSK3B and Alzheimer disease: In contrast, we see a twofold upregulation of p-GSK3β (Ser 9) in the hippocampus, prefrontal cortex, and cortex of old AD mice, with no significant changes in the cerebellum (Student’s two-tailed t-test, p < 0.001, n ≥ 4; Figures 8D–F).