Chicken Heart in CAGE Device (IMAGE) University of California - Berkeley Caption A heart removed from a chicken embryo sits in the CAGE device, which uses a sheet of graphene under the heart to measure tiny electrical fields produced when the heart beats. Credit Photo by Halleh Balch, Allister McGuire and Jason Horng 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.