VGF and Cognitive impairment: In human AD brain and cerebrospinal fluid (CSF), VGF and CHGA neuropeptides are downregulated and upregulated, respectively, compared to control brains (Higginbotham et al., 2020; Podvin et al., 2022; Quinn et al., 2023; Haque et al., 2023); moreover, reduced VGF neuropeptides correlate with cognitive impairment (Haque et al., 2023; Higginbotham et al., 2020).