Safety Dave Duerson won a Super Bowl as a cog in the 1985 Bears defense. In February 2011, Duerson, 50, texted to his ex-wife Alicia an odd request: "Please, see that my brain is given to the N.F.L.'s brain bank." When Duerson's body was found, there was a handwritten suicide note repeating the request. "I think David knew that inside of him there was something wrong," Alicia told the New York Times.