W.R. Kenan Jr. Professor of Chemistry, and a member of the Center for Alcohol Studies, studies reward and dopamine. Brain reward centers were first recognized when specific parts of the brain were found to support electrical self-stimulation, e.g., animals would voluntarily and emphatically press a lever to administer stimulation through an electrode in their brain. Only selective brain regions would support self-stimulation and it was later discovered that these areas were rich in dopamine. Addictive drugs were found to lower the threshold of self-stimulation in more detailed analysis. Wightman's studies on dopamine transporter knockout mice and self-stimulation effects on stimulated dopamine release do not agree with this concept.
Attention is important in addiction, and as a component of recognition of reward or punishment.
Koob's studies focus more on addiction and the balance between pleasure associated with positive reinforcement and responses to positive or negative affective states that lead to conditioned responses, or habits. Addiction may be a process driven by drug-induced changes in affect, driving adaptive behavioral responses in an effort to maintain homeostasis, e.g., normal healthy states. Drug abuse alters the normal state in two ways. The positive affective state of reward is reduced and the negative affective state of withdrawal is enhanced. These factors combine to promote additional drug taking behavior.