Amyotrophic lateral sclerosis (ALS) is characterized by progressive motoneuron loss. Autopsy from thoracic spinal tissues of sALS patients revealed a significant loss of large motoneurons while medium and small motoneurons were relatively unaffected. Using two-photon microscopy, we observed a soma hypertrophy of neonatal motoneurons in mice overexpressing mutant human G93A-superoxide...