Axon initial segments were immunohistochemically labelled using antibodies against Nav1.6 (the main sodium channel subtype found at the AIS) and antibodies against choline acetyltransferase (ChAT) to label spinal motoneurones in the ventral horn of the lumbar spinal cord in adult (~193 day old) presymptomatic ALS mice and aged-matched wild type (WT) mice (more details of all mice used can be found in Table 1). The gene discussed is CHAT; the disease is amyotrophic lateral sclerosis.