Smoking, Jokes, and the Soul

A small region of the brain called the insula may be a master regulator of actions, cravings, and emotional experiences.

David Ewing Duncan 02/22/2007

5 Comments

Want to quit smoking in a flash--and be instantly conscious of losing the urge to light up?

In Los Angeles, this happened to 19 smokers, though no one would want to emulate how they did it. Each had suffered damage to the insular cortex, a small section of gray matter deep inside the brain that seems to play a key role in processing actions, cravings, anticipation, and emotional responses--and making us aware of certain feelings.

The insula could be the repository of the soul, if such a place exists. (And the list of candidates is getting smaller, the potential seat of the soul having moved from "somewhere" inside people to the heart to the brain). By "soul" I don't mean a specific organ or "place" that is the essence of our spiritual being, or that makes constant contact with a deity--I'm talking about a physical ops center that makes us distinctly human and aware. Think of what the philosopher William James called "embodied recognition," the idea that specific emotional events cause the brain to activate subjective emotional experiences.

The two nodes of the insula in humans and other mammals are associated with the limbic portion of the brain, which is used to process hunger, pain, the smell of rotten food, and the touch of a mate, among other things. The insula is also involved in telling and responding to jokes.

In humans, the front section of the insula is comparatively huge and contains neurons not found in most other mammals. These seem responsible for an emotional element that causes conscious reactions. Pain might make us angry; touching a lover makes us happy and fires up the libido; smelling a rotten banana disgusts us; watching a tear-jerker movie makes us sad. The right-side insula apparently thickens in people who regularly meditate.

For some, anticipating a cigarette or a line of cocaine makes them crave the stuff.

These are highly specialized reactions that make us human--and account for actions both good and not so good, which is one way of defining the soul. Another way to look at it is that this proves there is no soul, and that actions and emotions are mostly programmed by the brain--which is what James suggested. (I plan to touch on this now and then in this blog--the issue of free will vs. the predetermination of the brain in influencing our actions and emotions.)

Now scientists at UCLA, led by Antoine Bechara, report in Science that damage caused by stroke and other neurological problems in 19 patients caused their craving for cigarettes to disappear in a puff. Bechara and other researchers conducting similar experiments suggests that the insula may be the key to treating addictions and other undesirable emotions and actions that apparently stem from this part of the brain.

Scientists must tread carefully, however, since shutting down all or part of the insula might also kill off "good" emotions, reducing us to mere beasts of the field, as the Bible might say--unaware that we want to eat a banana because we love bananas, or that we want to have sex because we enjoy it and perhaps love our partner.

Now, here's a question: if shutting down a few neurons may end an addiction or stop other sins both minor and deadly, what does that mean for the idea of a soul?

And how does that make you (and your insula) feel?