In Parkinson's disease, the cerebral cortex can take over tasks from a deeper part of the brain that is damaged, and where cells that make dopamine have been lost. That degree of compensation by the cerebral cortex determines how many complaints people have. This is evident from a publication by the Radboudumc in the Netherlands. Patients can stimulate this compensation by exercising, for example, and thus slow down the disease process.
It was already known that in Parkinson's disease, the cells in the brain that produce dopamine slowly disappear. Therefore, patients are given extra dopamine as a medicine. But only a limited link has been found between the loss of those cells, and the degree of complaints in Parkinson's. Even if all the cells are already broken, one person experiences mild symptoms, while another has many more symptoms. Researchers at the Radboudumc investigated whether there might be anything else going on.
They found that the outer part of the cerebellum, the cerebral cortex, can compensate for the loss of the cells that make dopamine for a long time to come. For example, the complaints are postponed, as it were. It turns out that the severity of complaints is clearly related to that compensation by the cerebral cortex. The more actively those tasks take over, the milder the slowness and the better the thinking goes. Doctors have long suspected that such a mechanism of compensation exists, but it has now been scientifically proven for the first time. (Source: Parkinsonvereniging)
This research has been published in Brain:
Clinical severity in Parkinson’s disease is determined by decline in cortical compensation. Martin E. Johansson, Ivan Toni, Roy P.C. Kessels, Bastiaan R. Bloem, Rick C. Helmich.