John Cena On Concussions, Possibly Donating His Brain For Research, Justin Bieber (Video)

- In the video above, TMZ Sports catches up with a very cautious John Cena while he was in New York City.

Cena is asked about concussions and if they're big in wrestling. Cena said concussions are an element of anything that involves contact. Cena also said he would be open to donating his brain to research because he's donated his body for other things. Cena said if he could do things to help people after he exists, he would be open to it.

In regards to rumors that Justin Bieber was supposed to wrestle in WWE a while back, Cena says it never happened but he's open to teaming with or going against Bieber.