20 September 2017: Optimizing multi-modal neuroimaging methods to examine and improve reward functioning in addiction

Travis Baker
Rutgers Center for Molecular and Behavioral Neuroscience
Rutgers University

Neurocognitive alterations to mesocorticolimbic reward function by drugs of abuse are thought to facilitate a progression towards excessive drug use. Despite efforts to identify methods to counteract such drug-induced neural alterations, brain-based treatments for this disorder remain underdeveloped and often ineffective. In this talk, I propose that the anterior cingulate cortex (ACC) putative function—selecting and motivating the execution of extended goal-directed behaviors—can be utilized as a biomarker for the abnormal reward processes underlying substance misuse. I will present support for this proposal utilizing the reward positivity as a quantifiable EEG metric of reward-related ACC function. First, people who abuse addictive substances produce a relatively small reward positivity to monetary incentives, and that this impairment is modulated by a genetic polymorphism that codes for the expression of dopamine D4 receptors. Second, drug rewards (puffs of a cigarette) elicit a relatively larger reward positivity than nondrug rewards (money) in abstinent smokers. Third, applying excitatory or inhibitory stimulation to a subject-specific frontal-cingulate reward pathway using robot-assisted fMRI-guided rTMS can alter the amplitude of the reward positivity elicited by drug and non-drug rewards. In sum, our efforts point to a decisive role of integrating multimodal neuroimaging methods as an early stage in treatment development for substance use disorders, with a highly sensitive EEG-based biomarker of addiction severity and treatment efficacy.