A fluorescent microscopy image of neurons, or nerve cells, generated by reprogramming skin cells of someone with Parkinson's disease (above, left) and those of a healthy person (above, right). The small structures in red in the image are dopaminergic neurons, a type of brain cell. These neurons play an important role in the control of brain functions, such as movement. The levels of such neurons are lower in the brains of people with Parkinson's disease. Researchers use such images to study why there is dopaminergic neuron loss in patients with Parkinson's disease. Parkinson's and Alzheimer's are the two most common ageing-related neurodegenerative diseases worldwide. For the first time, researchers have identified a link between two key proteins that are affected in both ailments. Both proteins act on a common pathway leading to cell death in the brain. This finding will allow researchers to work with companies to trial the use of drugs, which are already being used on patients, to target this pathway. This could provide a better treatment option for patients with Parkinson's disease, while helping prevent Alzheimer's disease, the researchers said. The research is led by the National Neuroscience Institute, in collaboration with Duke-NUS Medical School and the Agency for Science, Technology and Research (A*Star). It is funded by the National Medical Research Council's Translational and Clinical Research Flagship Programme.