SOD1 and amyotrophic lateral sclerosis: Comparison of SOD1 seeding activity in each sporadic ALS patient’s motor cortex versus thoracic cord specimens indicates the motor cortices gave shortened lag phases relative to those given by thoracic spinal cord at equally matched dilutions (Fig. 7), suggesting potentially more SOD1 seeding activity in the primary medial motor cortex of these patients relative to their thoracic cord at the end stages of their disease.