In May 2011, scientists announced that an autopsy of the brain of former Chicago Bears safety David Duerson, 50, who died from a self-inflicted gunshot wound, showed evidence of "moderately advanced" chronic traumatic encephalopathy, or CTE.

CNN: NFL wants players' suit over concussions dismissed

While Mitchell did not identify the researchers making the requests, among the institutions the family could donate Seau's brain to is Boston University's Center for the Study of Traumatic Encephalopathy, the research center that found former Chicago Bears safety Dave Duerson suffered degenerative damage to his brain because of repeated hits.

CNN: Junior Seau's death classified as a suicide

Before shooting himself, Duerson, a former Chicago Bears defensive back, left a note asking that his brain be studied for signs of trauma.

WSJ: Junior Seau: NIH Study Finds Football Star Had Brain Disease