Last week I moved from a Mac Mini to a MacBook Pro. I had a Thunderbolt display so the keyboard controls for brightness worked perfectly. But with the MacBook Pro you can only control its screen. I was really bummed with the fact that I couldn’t change the brightness of that huge display. That’s when i found out that the ‘control’ key does the trick.
So if you want to adjust the screen of your thunderbolt display just use control + F1 and control + F2