The motor symptoms seen in Parkinson’s disease occur due to the accelerated ageing of the neurons (brain cells) in the region of the midbrain, also known as Substantia nigra. These neurons produce a substance called dopamine that serves as a transmitter in the brain and plays an important role in the execution of movement and the control of our behaviour (e.g. reward or stress). By the time the diagnosis of Parkinson’s disease is made, many neurons have already degenerated. We know, however, that not only dopamine-producing neurons are affected, but also other neurotransmitters are involved in Parkinson’s disease, that can contribute to other symptoms such as depression.
Even though the exact cause of Parkinson’s disease is still unknown, researchers have discovered that genetic as well as environmental factors can contribute to the onset of the disease. It is thought that one fifth of all the cases have a genetic origin. Moreover, it is assumed that the interplay between our genetic makeup and environmental factors that we are exposed to during the course of our life can determine whether and when a person gets the disease.
Further research is needed in order to decipher the exact underlying causes of Parkinson’s disease.