What 9 common drugs including caffeine, weed, and booze do to your brain

A puff of this, and the world transforms into a colorful kaleidoscope of dancing patterns and waves of sound; a sip of that, and the muscles in your body relax like jello.

We know different drugs make us experience the world around us in very different ways - and their after-effects are often nowhere near as pleasant as the immediate results they produce.

So what exactly are these drugs doing to the brain to prompt these feelings?