A Disrupted Master Clock (image) Johns Hopkins Medicine Caption This is an illustration of the activity patterns of normal mice (left) and mice whose "master clock," or SCN, has been disrupted (right). Credit Cell Reports, Bedont et al. Usage Restrictions Permission required from Cell Reports. 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.