BOSTON (AP)Three NFL players announced Monday they will donate their brains and spinal cord tissue to a Boston University medical school program that studies sports brain injuries.

Even though dozens of former NFL players have agreed to donate their brains after death, center Matt Birk(notes) of the Baltimore Ravens, linebacker Lofa Tatupu(notes) of the Seattle Seahawks and receiver Sean Morey(notes) of the Arizona Cardinals are the first active players to do so.

The goal of the universitys Center for the Study of Traumatic Encephalopathya collaborative venture between BU Medical School and Sports Legacy Instituteis to better understand the long-term effects of repeated concussions. 

When you are active, your contractwhat you get paidis based on the perception of your health, and no player wants to be perceived as being prone to concussions, said Chris Nowinski, the centers co-director. Thats why I am so impressed with these guys. I hope they are the first of many.

More than 150 former athletes, including 40 retired NFL players, already are in the programs brain donation registry.

One of the most profound actions I can take personally is to donate my brain to help ensure the safety and welfare of active, retired, and future athletes for decades to come, said Morey, who along with Tatupu has been listed on NFL injury reports in past seasons with injuries described as concussions.

Doctors see sports-related brain trauma as a growing health crisis due to the discovery of the neurodegenerative disease chronic traumatic encephalopathy in a number of athletes who have recently died. The condition is caused by repetitive trauma to the brain.

This is a bigger threat than we are acknowledging, said Nowinski, who suffered concussions as a college football player and professional wrestler.

Sufferers may experience memory loss, emotional instability, erratic behavior, depression and impulse control problems, progressing eventually to full-blown dementia.

As part of the program, the players will be interviewed annually for the rest of their lives so researchers can examine the relationship between clinical symptoms and pathology.

Birk, Tatupu and Morey have all played in the Pro Bowl, making their pledge all the more significant, Nowinski said. He hopes their participation sparks locker rooms conversations with their teammates about the dangers of head injuries, he said.

Morey said players need to understand the serious implications of playing through concussions or not reporting them because of the cumulative effect of such injuries.

He said his interest in the issue was sparked in part by an article on former New England Patriot Ted Johnson, who received numerous head injuries during his 10-year career.

I played with Ted. He was one of the best guys in the locker room, Morey said. He took me under his wing and made me feel part of the team when I was just a practice squad player. I think that was sort of the impetus for me to kind of make sure that I did my due diligence, understanding the effects of concussions and report back to the players union.