<div id="subtitle">More NFL players pledge to donate brain after death for concussion study</div><div><p>Pro Football Hall of Famer Mike Haynes and current Chicago Bears linebacker Hunter Hillenmeyer are among more than a dozen NFL players who have pledged to donate their brain and spinal cord tissue for concussion research.</p><p>Retired players Zach Thomas, Kyle Turley and Conrad Dobler also have said they'll help the Center for the Study of Traumatic Encephalopathy at Boston University School of Medicine.</p><p>The wife of Hall of Famer John Mackey pledged to donate his brain after his death. Mackey has dementia.</p><p>In December, the NFL and its players association said they would support the center's research and encourage players to participate. The NFL said it was willing to give $1 million or more to the center.</p><p>Current NFL players Sean Morey of the Cardinals, Matt Birk of the Ravens, and Lofa Tatupu of the Seahawks earlier had agreed to donate their brain for research.</p><p>"The only way we will truly understand the long-term effects of repetitive head trauma in football is to study a large group of athletes throughout their lives and then examine their brains following death," said Dr. Robert Stern, a co-director of the center.</p><p>The BU brain researchers have said they found links between repeated head trauma and brain damage in boxers, football players and a former NHL player — and the group has been critical of the NFL's stance on concussions.</p><p>NFL commissioner Roger Goodell met in October with a member of the center to discuss concussions and the BU project.</p><p>The NFL took several steps this season to ramp up its attention to concussions in the aftermath of a congressional hearing on the topic and as high-profile players such as Ben Roethlisberger, Kurt Warner, Clinton Portis and Brian Westbrook were sidelined by head injuries.</p><p>The league's steps included stricter return-to-play guidelines detailing what symptoms preclude someone from participating in games or practices; a mandate that each team select a league- and union-approved independent neurologist to be consulted when players get concussions; and the departure of the two co-chairmen of the NFL's committee on brain trauma.</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=68256638&bid=informcom" /></div><div id="copyright"><div>

Copyright 2010  <a href="http://www.ap.org">AP News</a></div></div>