Picture and text from "Evidence Aggregates Against Alpha-synuclein in Varied Neurologic Disorders" by Richard Robinson. Neurology Today, Vol 4 (1) 7-11, 2004. Dr.John Trojanowski: "What we think goes wrong is that when alpha-syneclein aggregates, it is disabled or taken out of action, and can't interact with vesicles" or other factors in the neuron, leading to a loss of function and then neurodegeneration.