Fig. (IMAGE) Osaka University Caption Sperm sense an "electrical signal," resulting in changes in motility. Intracellular enzyme activity is also upregulated in response to the electrical signal. Credit Osaka University 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.