Junior Seau's family plans to donate his brain to science, San Diego Chargers chaplain Shawn Mitchell announced Thursday evening.
Seau's family said it is not looking to discover anything new about their son or what led to his death, but relatives did say they hope others will benefit from the study of his brain down the road.
Jacopo Annese, director of the University of California at San Diego's Brain Observatory, said that while there is no definitive link between blows to the head and such severe health problems as depression, dementia and Alzheimer's disease, he did say there was strong scientific and anecdotal evidence for such a connection.
"However ghoulish it may appear to the majority of the public, the work that is conducted postmortem is essential to validate this hypothesis, because the important clues are at the cellular-level, and we can't see these with MRI, but we can with our microscopes," Annese told ABCNews.com.
While research methodology has not changed dramatically, the questions have evolved, offering clues into the potential lifetime adverse effects of hits and blows to the head.
"Searching for the link between traumatic injury and more subtle and insidious effects like depression, suicide and dementia," said Annese, "has been particularly crucial in the world of sports, where unprecedented body mass and acceleration create the scenario for severe trauma if there is a collision."
On Thursday, the San Diego County Coroner ruled former longtime NFL linebacker Junior Seau's death a suicide.
Officials conducted a forensic autopsy, which includes "a full examination of a decedent's body and organs and collection of specimens for laboratory studies."
Seau, 43, was found dead of a self-inflicted gunshot wound to the chest Wednesday morning at his Oceanside, Calif., home.
The 12-time former Pro Bowl player's death came one day before more than 100 former NFL players filed a federal lawsuit in Atlanta, claiming the league did not properly protect them against concussions and did not properly provide medical care after they finished their careers.
The Associated Press reported that the league has said any accusation that the NFL intentionally misled players was not true.
Seau's death echoes that of other athletes in hard-hitting sports, including Chicago Bears football player Dave Duerson. Duerson shot himself in the chest in February of last year. Duerson's family filed a wrongful death suit against the NFL, stating the league did not protect players against concussions.
On Thursday morning, rumors swirled as to whether Seau shot himself in the chest so that his brain could be studied. He didn't leave a note, but Sports Illustrated reported Thursday that Boston University's Center for the Study of Traumatic Encephalopathy requested to study Seau's brain. The sports mag later clarified the statement by saying the center attempts to examine the brains of all athletes who die after making a career playing hard-hitting sports. It is not known where Seau's brain will be sent for study.
"It is our policy to not discuss any completed, ongoing or potential research cases unless at the specific request of family members," the center said in a statement Thursday. "Our primary goal is to learn more about the long-term effects of repetitive brain trauma by conducting meaningful scientific research. At this time our thoughts and prayers are with Mr. Seau's family, his many friends and former teammates."
Several former NFL players have committed suicide in recent years, and many experts believe the deaths could be related to repeated blows to the head. In addition to Duerson, ex-Pittsburgh Steelers offensive lineman Terry Long and Philadelphia Eagles defensive back Andre Waters took their own lives. Chronic traumatic encephalopathy, or CTE, a degenerative and progressive disease found in people who have experienced multiple blows to the head, has shown up in the brains of several former athletes who committed suicide, including Duerson.
The condition has brain characteristics that resemble those of Alzheimer's, Parkinson's and Lou Gehrig's disease.
As of October, more than 500 current and former professional athletes agreed to donate their brains to the VA Brain Bank, which works in affiliation with Boston University's Center for the Study of Traumatic Encephalopathy.
Annese said the Brain Observatory at UCSD has been in contact with several athletes who are considering participating in the brain donation program.
"Like Mr. Seau, they feel that they personally hold many of the answers needed to know how to make their sport safer for future generations," said Annese. "The examination of the brain is only the final and definitive chapter of a long narrative that we create working with our participants."
The average life expectancy of a retired football player is 58 years old, according to the NFL Players Association. That is a stark contrast to the average American man's life expectancy of 75 years, according to government data based in 2006.
While Seau was never listed on any NFL injury report as having a concussion, according to ESPN, his family tells a different story. When asked whether Seau had experienced any concussions in his career, his ex-wife, Deboer, said, "Of course he had," according to the Associated Press. "He always bounced back and kept on playing. He's a warrior. That didn't stop him. I don't know what football player hasn't. It's not ballet. It's part of the game."
Repeated blows to the head may disturb neurotransmitters that affect mood, and may also damage parts of the brain that have to do with impulse control and the ability to weigh the long-term consequences of decisions.
Nevertheless, until more research is done, experts caution against definitively linking the hits Seau experienced in his career and his suicide.
In 2009, the NFL instituted new rules that require clearance from independent neurologists to allow players who endured concussions to return to the field. The league also imposed stricter guidelines to reduce the number of helmet-to-helmet hits.
"What happened to Junior Seau is terribly sad," said Annese. "The least us scientists can do is to match his dedication to his sport and his community with our own dedication to research, finding the reasons for such tragedy, so that it does not have to happen again."