Further, associations between AD neuropathology and depression remain controversial (Li et al., 2017; Babulal et al., 2020; Saldanha et al., 2021; Pomara et al., 2022).The links between AD and depression (Ledo et al., 2016, 2013; Dafsari and Jessen, 2020) and previous findings of the association between exercise and antidepressant activity prompted us to investigate whether fndc5 expression could be dysregulated in depression. This evidence concerns the gene FNDC5 and Alzheimer disease.