Optical Fiber (image) Howard Hughes Medical Institute Share Print E-Mail Caption An optical fiber (gray bar) threaded into the brain of a mouse (green) revealed activity of neurons involved in thirst. Scale bar equals 1 millimeter. Credit C. Zimmerman et al./Nature 2019 Usage Restrictions Must use credit. Share Print E-Mail 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.