Accordingly, previous autopsic studies have shown neuropathological involvement of spinal laminae I, II and III in Parkinson's disease, where nociceptive neurons and interneurons show a-syn pathology.94 This is consistent with alpha-synuclein pathology affecting nociceptive amyelinic fibres early in Parkinson's disease,94 which were reported to accumulate alpha-synuclein in both humans and rodents.95,96. This evidence concerns the gene SNCA and Parkinson disease.