SNCA and Parkinson disease: Examining the progression of the dissemination of α-synuclein pathology in postmortem brains, they found that in addition to the dorsal motor nuclei of the vagus (DMV) and glossopharyngeal nerves, the OB and anterior olfactory nucleus (AON) were among the first sites at which α-synuclein pathology is found in PD patients [20].