Brains cells affected by Parkinson's disease die prematurely because they are prone to burning out "like an overheating motor", according to new research.
Scientists writing in the journal Current Biology, said they found the cells targeted by the disease require unusually high levels of energy to carry out their job of controlling movement.
Parkinson's is a degenerative disease for which there is currently no cure.
The Canadian researchers studied the disease in mice and focused on the role of mitochondria, which enable cells to grow and release chemicals such as dopamine - a compound Parkinson's sufferers are deficient in.
They found the complex structure of neurons in the substantia nigra region meant mitochondria were constantly working at "burnout rates" and so were more likely to degenerate and die with age.