GRIA1 and amyotrophic lateral sclerosis: This study has employed a highly sensitive in situ hybridisation method (BaseScope) to examine the expression of AMPAR subunit mRNA transcripts (GluA1–4) at a single‐cell level in post‐mortem spinal cord (anterior horn cells), motor cortex (BA4) and prefrontal cortex (BA9) tissue from sporadic, SOD1 I114T and C9orf72RE ALS patients (three patients for each ALS cohort).