Parkinson's disease is a brain disorder that leads to difficulty with walking, balance and coordination. There is currently no cure, but scientists in Pittsburgh, PA have an ambitious plan to develop a treatment based on the placebo effect. NPR science correspondent, Jon Hamilton, tells the story of how this plan came to be. It involves a batch of illegal drugs, the rabies virus, and figuring out what makes a monkey really happy. Watch the video of the cyclist with Parkinson's disease here: https://bit.ly/3GPZ6PKEmail the show at ShortWave@NPR.org.