The co-localization signal, defined as an αSyn-PLA signal within the PGP9.5 positive nerves (Fig. 2a), was the most frequent, while the dotted one, defined as the signal located in proximity to degenerated nerve fibers or interposed between nerve fiber breakpoints (Fig. 2a), was observed exclusively in PD and MSA, not in AP-Tau or HC (Fig. 3a). Here, MAPT is linked to Parkinson disease.