Former Stanford and Raiders linebacker Jon Alston left football after having four concussions in less than 12 months and during that time extensively researched the impact of head trauma and now owns his own movie production company, Dream America Pictures, with an independent movie scheduled to be released in July.

Here are the dates of the four concussions (the first two with the Raiders, the second two with Tampa Bay) which led to Jon Alston giving up football:

10-25-09 vs. New York Jets

11-1-09 vs. San Diego

8-14-10 vs. Miami

8-21-10 vs. Kansas City

Alston played sparingly the week after the Nov. 1 concussion, didn’t feel right and was then placed on injured reserve, ending his season. He signed with Tampa Bay as a free agent in the offseason.

Definition: Chronic Traumatic Encephalopathy

A degenerative brain disease that results in behaviors similar to Alzheimer’s disease. Believed to have a clear environmental cause (repeated brain trauma) rather than a genetic cause. The only preventable form of dementia.

EDITOR’S NOTE: Here are excerpts of an interview with Raiders beat writer Jerry McDonald in which Alston touches on his experiences with head trauma and how the NFL and its players should consider dealing with it:

On his fourth and final concussion:

“The hit was not bad, but I was still having bad headaches. Something was wrong. I could have tried to fake like I was OK, but I had a decision to make. I knew once I made the decision to tell I had another one, that was probably the end of my career. Based on my knowledge of what is happening in people’s brains and CTE (Chronic Traumatic Encephalopathy) I knew that the only right decision, if I cared about myself, was to say something.

His current health:

“I had a really hard time for the first six-to-eight months coming out of it. I was having pretty bad headaches, memory loss, nausea, some really tough stuff. Now I feel fine. I run on a regular basis, long distances. I still lift. I’ve lost weight to be in better health. I think being in shape helps me to be clear in mind, as well as having other outlets and good, positive people around me.

Making a year off mandatory for concussions which result in being placed on injured reserve:

“I applaud the NFL’s efforts, putting pamphlets in lockers, talking to guys about concussion safety. I think what would have been beneficial for me, and the league should take the stance that if you go on injured reserve with a concussion, it should be a mandatory year off. The game has done a lot of good things for a lot of people, myself included, but it would be a shame to see the game ruined by this issue.

The impact of Junior Seau’s death:

“I figured it would take larger-named guys, tragedies, that would start to bring light to this issue. A guy like Junior took a lot of small hits over a very long period of time. Also some big hits. And gave some. I met him in 2001 and was in awe of the guy. He’s one of the guys that made me want to play in the NFL, and it’s terrible to see.”

The combination of head trauma and career transition:

“(Chronic Traumatic Encephalopathy) is real. If your identity is in football and you’re leaving, I don’t care if you’re a college or pro athlete, it’s the love of your life. You’re going to experience a depression. It’s like a divorce. Now imagine that with CTE, and trying to transition into another world. Depression is real, and with CTE it’s exacerbated. If your brain is damaged and you don’t talk to someone, you might not even be aware of what’s going on when you go to those dark places because of what’s going on in your brain. It’s going to be a very tough fight. I suspect when researchers are able to look at Junior Seau, with an onset of CTE . . . God willing, we won’t see too many more of these cases.”

The potential impact of technology:

“If we’re going to see the game played like it is, we’re going to need better technology. We need to protect heads. Is it possible to do that? Is it possible for someone to come up with a helmet that stops the brain from being jolted? I don’t know, but there area a lot of smart people out there right now and it’s going to be a very profitable business. The difference between leather helmets and what we have now, that’s basically what we need going forward.”