Figure 2.

Schematic diagram depicting a possible central cascade leading to cell-to-cell transfer of α-SYN. The central process is likely affected by several other disease mechanisms that have already been implicated in PD (shown inside the circle) and that form an interdependent network of molecular events, which in combination or each on their own can promote the central cascade. Weak genetic risk factors and aging are depicted as potential triggers or promoters of cell-to-cell transfer of α-SYN (for details of the different mechanisms, see text).