Researchers have established how a protein called alpha-synuclein, which is closely associated with Parkinson's Disease, functions in healthy human brains. By showing how the protein works in healthy patients, the study offers important clues about what may be happening when people develop the disease itself. Parkinson's disease is one of a group of conditions known as "protein misfolding diseases," because they are characterized by specific proteins becoming distorted and malfunctioning. These proteins then cluster into thread-like chains, which are toxic to other cells.