Sorry if the title is a bit deceptive, but a while back I remember reading somewhere about different pleasure pathways in the brain. One of them is quick and more intense and is involved with pleasures like food and sex. The other one goes through a longer section of brain and takes longer to activate. I'm not sure exactly what activates it. I do remember reading that introverts are more likely to use the long pathway than extroverts (although I think both probably use the short one the most).
Does anybody know what I'm talking about and where this information might be?