GSK3B and Alzheimer disease: When hippocampal neurons are treated with the Aβ peptide (which extracellular accumulation is a hallmark of Alzheimer’s disease), there is an increase in cell apoptosis as well as in GSK-3β activity, whereas the intracellular levels of β-catenin and the transcription of Wnt-target genes are reduced (Garrido et al., 2002; De Ferrari et al., 2003; Alvarez et al., 2004).