PVALB and Alzheimer disease: In Alzheimer’s disease, somatostatin expression is decreased by 50% in the AONca and co-localizes with amyloid β (Saiz-Sanchez et al., 2010), whereas parvalbumin and somatostatin levels are up- and downregulated, respectively, in the piriform cortex (Saiz-Sanchez et al., 2015, 2016).