Methods of treating individuals suspected of suffering from diseases, conditions or disorders of the Central Nervous System including nerve damage are provided wherein stable, homogeneous post-mitotic human neurons are into the individual's brain or at or near a site of nerve damage. Pharmaceutical compositions of stable, homogeneous post-mitotic human neurons and a pharmaceutically acceptable medium are also disclosed. Methods of generating non-human animal models of human CNS diseases, conditions or disorders by implanting stable, homogeneous post-mitotic human neurons into the brain of a non-human animal are disclosed. Non-human animals eith stable, homogeneous post-mitotic human neurons implanted in their brain are also disclosed.