Scientists have long sought to understand how certain animals, such as zebrafish, are able to regrow nerve fibers and regain lost motor function after spinal cord injury. In humans, these injuries are irreparable and result in permanent loss of function, such as paralysis. An international team led by Daniel Wehner of the Max Planck Institute for the Science of Light and the Max-Planck-Zentrum für Physik und Medizin in Erlangen, Germany, has been able to show that a group of previously little-studied proteins inhibit regeneration of the central nervous system in mammals by altering the structural and mechanical properties of the wound tissue.