It is not difficult to envision how a signaling molecule such as GDNF, which has potent effects on neuronal maturation, cell survival and synapse formation, can effect cognitive functions; and if aberrantly or insufficiently expressed or secreted, contribute to cognitive decline (Ibáñez & Andressoo, 2016; Pertusa et al., 2008). The gene discussed is GDNF; the disease is Mental deterioration.