One of the most pervasive mistakes is to believe that our visual system gives a faithful representation of what is "out there" in the same way that a movie camera would.

It turns out that dopamine is a chemical on double duty in the brain. Along with its role in motor commands, it also serves as the main messenger in the reward systems, guiding a person toward food, drink, mates, and all things useful for survival. Because of its role in the reward system, imbalances in dopamine can trigger gambling, overeating, and drug addiction - behaviors that result from a reward system gone awry.

When one part of the brain makes a choice, other parts can quickly invent a story to explain why. If you show the command "Walk" to the right hemisphere (the one without language), the patient will get up and start walking. If you stop him and ask why he's leaving, his left hemisphere, cooking up an answer, will say something like "I was going to get a drink of water."

Just give the brain the information and it will figure it out.

Even though the outside world has not changed, your brain dynamically presents different interpretations.

Interestingly, schizophrenics can tickle themselves because of a problem with their timing that does not allow their motor actions and resulting sensations to be correctly sequenced.

I know one lab that studies nicotine receptors and all the scientists are smokers, and another lab that studies impulse control and they're all overweight.