Did you know you can be considered a "pot-head" without ever touching, let alone smoking, marijuana? When early neuroscientists went looking for the mental hardware that allowed the body to respond to the active ingredient in the cannabis sativa plant (called THC), they found much more than they were bargaining for. They did in fact identify a perfectly-shaped receptor in the brain. Puzzled at why it would exist (surely the human body was not designed with cannabis-intake in mind?), they went on to discover that the body itself makes a cannabis-like substance, called an endocannabinoid, and that it is part of a complex system regulating appetite, pain, pleasure, and immunity. So, technically, your brain is already wired for pot, and your body produces it all by itself.