NFL, union try to change culture on concussions  NFL, union try
to change culture on concussions FILE - In this Sept. 23, 2012,
file photo, Washington Redskins quarterback Robert Griffin III
hits the turf after being sacked during the first half of an NFL
football game against the Cincinnati Bengals in Landover, Md.
(AP Photo/Alex Brandon, File) NEW YORK (AP) - A high-profile
rookie quarterback gets slammed in the side of the head and his
Super Bowl-winning coach describes him as "shaken up."  An All-
Pro receiver admits to getting "my bell rung pretty good" as
being part of the game, and if a player gets concussed, "you've
got to keep on playing."  NFL executives want to change the
culture of the league - and all of football - to reduce head
injuries. So far this season, there's evidence it's going to be
a tough road.  "The challenge is everywhere and for everyone in
the sport," says perennial Pro Bowl defensive back Troy Vincent,
now a league executive. "It's a shared responsibility and a
personal accountabi