Devices and methods for treating diseases associated with loss of neuronal function are described. The methods are designed to promote proliferation, differentiation, migration, or integration of endogenous progenitor stem cells of the central nervous system (CNS). A therapy, such as an electrical signal or a stem cell enhancing agent, or a combination of therapies, is applied to a CNS region containing endogenous stem cells or a CNS region where the endogenous stem cells are predicted to migrate and eventually reside, or a combination thereof.