PPIB and amyotrophic lateral sclerosis: Post-mortem cervical spinal cord and prefrontal cortex (BA9) sections from three C9ORF72 mutation-carrying ALS patients and three age-matched controls with no known neurodegenerative disease were treated with fluorescence in situ hybridization (FISH) probes against AMPAR subunits and the positive control enzyme PPIB (Supplementary Fig. 7).