To determine if ALS mutant FUS expression in the τONhFUSR521C and hFUSP525L mice was associated with MN degeneration, we used an antibody against choline acetyl transferase (ChAT) to visualize and count spinal MNs at lumbar level 5 (L5; Fig. 3a). Here, CHAT is linked to amyotrophic lateral sclerosis.