Photo of researchers (IMAGE) Karolinska Institutet Caption From left: First author Silke Eisinger and last author Mikael Karlsson from Karolinska Institutet in Sweden. Credit Mitch Eisinger 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.