Definitely look into the nucleus accumbens; the striatal nuclei have a good
bit to do with reinforcement/conditioning. Also, if you are looking for
a bit more complex of a study, I would check the diffuse modulatory systems.
While I am most familiar with the dopaminergic system, I imagine that other
systems of modulation are similarly involved.
I would be surprised if the amygdala wasn't pretty involved as well.
Justin
