The invention discloses a family of peptides termed NRP compounds or NRPs that can promote neuronal migration, neurite outgrowth, neuronal proliferation, neural differentiation and/or neuronal survival, and provides compositions and methods for the use of NRPs in the treatment of brain injury and neurodegenerative disease. NRP compounds can induce neurons and neuroblasts to proliferate and migrate into areas of damage caused by acute brain injury or chronic neurodegenerative disease, such as exposure to toxins, stroke, trauma, nervous system infections, demyelinating diseases, dementias, and metabolic disorders. NRP compounds may be administered directly to a subject or to a subject's cells by a variety of means including orally, intraperitoneally, intravascularly, and directly into the nervous system of a patient. NRP compounds can be formulated into pharmaceutically acceptable dose forms for therapeutic use. Methods for detecting neural regeneration, neural proliferation, neural differentiation, neurite outgrowth and neural survival can be used to develop other neurally active agents.