SOD1 and amyotrophic lateral sclerosis: Structural abnormalities in the dendritic arbors and/or dendritic spines of neurons from the most widely used ALS rodent model, the hSOD1G93A transgenic mouse (SOD1), have been reported in upper MNs from the motor cortex [20, 30, 53, 58] and medial pre-frontal cortex (MPFC) [57], as well as lower MNs in the brainstem [69] and spinal cord [40].