i work as a stand up comedian. Nothing is more rewarding than to performs in front of a live audience, usually speaking directly to them.
That's great, I was wondering if there is anything in the brain that helps with comedy?
It has nothing to do with the brain. All you have to do is to  recite a grouping of humorous stories, jokes and one-liners typically called a monologue, routine or act.
That's great, does one have to learn a special skill to become a professional comedian?
Not really, as long as you can  provide a steady stream of laughs
Fantastic, when did people start to use comedy as a form of entertainment?
I am not sure about the time but it can be traced back to the origin as found in the Ancient Greece