Since James Parkinson first described his eponymous disease, our knowledge of its pathophysiology has grown enormously. However, in clinical settings, many of the original concepts remain in use, and diagnosis is still focused on the motor features arising due to the loss of dopaminergic neurons in the substantia nigra. Although these concepts have been useful for the field, enabling the development of a panoply of highly efficacious symptomatic therapies, they might have also hindered the development of disease modifying therapies, which require a deep understanding of the underlying biology. Neuropathologically, the field has focused on Lewy bodies and the tools used to identify them. It has also centred on the notion that Lewy bodies are toxic and contribute to the disease.
