Fiber Crossings Ahead: Key Enzymes Affecting Nervous System Pathway Identified (IMAGE) University of Tsukuba Caption University of Tsukuba researchers found the absence of enzymes key for corticospinal tract guidance, Sulf1 and Sulf2, results in abnormal anatomy of the corticospinal tract and impairments in fine motor function. The corticospinal tract of Sulf1/Sulf2 knockout mice showed abnormal fiber crossing at the pyramidal decussation. As a result, bilateral movement was seen when stimulating only one side of the brain, and mice had impaired fine motor control. Credit University of Tsukuba Usage Restrictions Unauthorized use is prohibited 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.