An immunocytochemistry study showed diminished perisomatic GABAergic terminals in brain sections from both AD patients and APP/PS1 transgenic mice, especially on cortical neurons adjacent to amyloid plaques, implicating the loss of GABAergic neuronal function in AD (Garcia-Marin et al., 2009; Ramos-Miguel et al., 2015). Here, PSEN1 is linked to Alzheimer disease.