Profiles of Neuroaffective Responding to Natural Reward-Predicting Cues and Alcohol Images in Alcohol Use Disorder: An Event-Related Potential Approach.

BACKGROUND AND AIMS: Incentive salience attribution (ISA) is the process by which the cues associated with reward take on value themselves. Individual differences in ISA are known to predict reward seeking and consuming behavior in animals and humans, suggesting prognostic potential in use disorders like alcohol use disorder (AUD). Since AUD etiology is thought to involve changes in natural (e.g., food) reward processing as much as alcohol-related processing, current research tested if differences in natural reward cue ISA are apparent, and predictive of behavior, in AUD.

METHODS: 30 individuals meeting AUD criteria and reporting heavy alcohol consumption on timeline follow-back (TLFB) participated. Subjects completed a validated ISA task wherein pictures depicting inherently appetitive, aversive, or emotionally neutral content are shown along with pictures that are less evocative but are predictive of reward (candy) delivery and (in this study) also alcohol images. To capture individual variations in ISA, a picture-elicited neural response that scales with picture salience - the late positive potential (LPP) - is indexed and then submitted to k-means clustering to classify different modulation profiles.

RESULTS: Replicating prior work, clustering indicated a 2-group solution where an "F>P" (n=14) group showed enhanced LPPs for food-predicting, relative to standard appetitive, pictures and an "F<P" group (n=16) showed reduced LPPs for food-predicting pictures. Also replicating prior work, both groups showed typical enhancement for appetitive and standard aversive, relative to neutral, pictures; and contrary to expectations, both also showed minimal LPP enhancement for alcohol pictures. Examining behavioral correlates of F>P versus F<P status, groups did not differ in reward consumption during the task, nor did they differ in AUD symptoms or weekly drinking per TLFB. Finally, while the LPP was not enhanced for alcohol pictures, enhancement for alcohol relative to neutral pictures was observed for an earlier (P300) neural response - and this was consistent across F>P and F<P groups.

CONCLUSIONS: Similarly sized groups of individuals who were more versus less responsive to natural reward cues is consistent with prior studies in non-AUD samples. At the same time, the lack of commensurate differences in task reward consumption differs from those studies, and could reflect change in natural reward processing in individuals with AUD. Implications for continued research are discussed.