Cells and Electric Field (image) University of California - Berkeley Caption The top image shows a patch of epithelial cells. The white lines in the middle image mark the electric current flowing from positive to negative over the cells. The bottom image shows how the cells track the electric field, with blue indicating leftward migration and red signaling rightward movement. Credit Images by Daniel Cohen Usage Restrictions All rights reserved. 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.