An innovative gene therapy treatment for Parkinson’s seems to relieve symptoms by rewriting the brain, scientists have found. Following the success of the therapy study, the researchers are planning a larger trial to start at the end of 2019.

A 2011 study published by the Feinstein Institute for Medical Research in New York found that a gene therapy designed to turn down the activity of the subthalamic nucleus improved motor control for those with Parkinson’s.

While the researchers determined that the treatment reduced the symptoms of Parkinson’s for more than a year in participants, they did not understand how. Since that point, they have used PET scans to compare the brains of 15 individuals who received the therapy with 20 who only received placebos.

Those who undertook the therapy had new brain connections which weren’t seen in the placebo group, and are not found in healthy individuals. According to the researchers, this means that the therapy allows those with Parkinson’s to form new brain circuits for controlling movement.