Sleep spiral (IMAGE) University of California - Santa Cruz Caption Data-driven graphic showing sleeping postures every 20 seconds and accompanying 30-second segments of EEG traces in the background. Credit Graphic by Jessica Kendall-Bar Usage Restrictions For use only with news coverage of this research and award. License Original 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.