For example, in superoxide dismutase 1 (SOD1) rodent models of ALS, excessive glutamatergic neurotransmission and associated dendritic and dendritic spine structural abnormalities have been observed in upper and lower MNs long before significant MN death16, 17, 18, 21, 22. The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.