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?
Comedy
In a modern sense, comedy (from the , "kōmōidía") refers to any discourse or work generally intended to be humorous or amusing by inducing laughter, especially in theatre, television, film, stand-up comedy, or any other medium of entertainment. The origins of the term are found in Ancient Greece. In the Athenian democracy, the public opinion of voters was influenced by the political satire performed by the comic poets at the theaters. The theatrical genre of Greek comedy can be described as a
Stand-up comedy
Stand-up comedy is a comic style in which a comedian performs in front of a live audience, usually speaking directly to them. The performer is commonly known as a comic, stand-up comic, comedian, comedienne, stand-up comedian, or simply a stand-up. In stand-up comedy, the comedian gives the illusion that they are dialoguing, but in actuality, they are monologuing a grouping of humorous stories, jokes and one-liners, typically called a shtick