Reconciling Braak’s model of Parkinson’s disease with a prion-like spread of alpha synuclein pathology

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a progressive accumulation of intraneuronal alpha synuclein (αsyn). The development of the underlying pathology of PD has been demonstrated to follow a distinct course throughout the brain. Recent evidence demonstrating the cell-to-cell transfer of αsyn has led to the suggestion that a prion-like process may mediate the pathological progression of PD. Here we highlight some of the recent advances in the transmissibility of αsyn and reconcile these findings with Braak’s model of PD progression.