PTTH Neurons (IMAGE) University of Würzburg Caption PTTH neurons (green) connect the circadian clock (magenta) of the brain with the peripheral clock in the prothoracic gland. Credit Photo: AG Wegener 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.