For the highly intelligent, their anterior insulae and anterior cingulate cortices play bigger roles in the movement of information than in less intelligent brains.
When someone is craving a cigarette, there is a lot more activity in the posterior cingulate cortex, a major node in the default mode network of the brain.
Scientists are increasingly confident that the neurological root of the disorder is a small hook of tissue towards the front of the brain called the anterior cingulate cortex.