Promising biotherapeutic approaches to UMN pathology in ALS, including neural progenitor cells11 and adeno-associated virus (AAV) expressing small-hairpin RNA to suppress mutant superoxide dismutase-1 (SOD1)3, have been surgically injected into the motor cortex of ALS rodents, resulting in significantly increased lifespan. Here, SOD1 is linked to amyotrophic lateral sclerosis.