The illustration shows a histological section from three dopamine cell transplants in the rat brain affected by Parkinson's disease. An artistic illustration shows how the transplanted cells are controlled by a new gene, so that they can be steered externally using a drug. This allows the nerve cells' function to be studied with unrivalled exactitude in the brain using an implanted electrode. With the help of this technique, the Lund researchers have been able to increase the dopamine cell transplant's function to a level where the animal has been completely restored. Furthermore, they have also used this technique to identify the exact signalling pathway that gives rise to the most common side effects that patients experience as a result of this treatment.