Study Investigators (IMAGE) Washington University School of Medicine Caption From left, co-first author Bryan A. Copits, Ph.D., Michael R. Bruchas, Ph.D., and co-first author Edward R. Siuda used light to activate opiod receptors in the brains of mice. Credit Robert Boston Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.