Dr. Gary Steinberg

And there's so many other sports where

which benefit in the same way as football or boxing.

Why not participate in those?

That's my feeling, but I know it's a controversial subject.

I don't think you need to worry in general, especially if your symptoms resolve within a relatively short period of time.

Such as?

How long?

A day or two?

Yeah, I mean, even if you have a mild concussion and you recover within a day or two, I don't think there's any need to worry or get a scan.

And it's a commonplace occurrence.

You know, I'm going to take issue with you at that because the prior notion, of course, was that once nerve cells in the brain die, they don't regenerate.

And for a long time, it was thought you don't produce any new nerve cells, any new stem cells in the brain.

And we used to think after an injury or a disease like a stroke or

when that tissue was damaged and you were paralyzed or you couldn't talk, that there was no way to recover, that those circuits were dead.

It turns out that is not true.

And we are learning that, I think, in recent years.

When I trained, there was no hope to restore function in patients who had a stroke, traumatic brain injury, spinal cord injury.

And other diseases, ALS, Lou Gehrig's disease, Parkinson's disease.

Now we are learning that there is hope.

We know that stem cells do form in the adult brain.