Exercising Neurons (IMAGE) Massachusetts Institute of Technology Caption MIT scientists find that motor neuron growth increased significantly over 5 days in response to biochemical (left) and mechanical (right) signals related to exercise. The green ball represents cluster of neurons that grow outward in long tails, or axons. Credit Angel Bu Usage Restrictions Images are made available to non-commercial entities, press and the general public under a Creative Commons Attribution Non-Commercial No Derivatives license. You may not alter the images provided, other than to crop them to size. A credit line must be used when reproducing images. 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.