In the reward cue AS task sensitivity to reward

In the reward cue AS task, sensitivity to reward cue was used to increase top-down or executive cognitive control in inhibiting a prepotent response (saccade). The incentive used in this study was relatively small ($10 total upon task completion), and no feedback was provided to participants on whether an incentive was earned for correct antisaccade performance on a given trial, yet reward cue enhanced behavioral AS performance and influenced associated dihydrofolate reductase activation in predicted ways. Motivational factors that enhance inhibitory control may take different forms. For example, a study of adolescent marijuana users found that motivation in the form of hearing and reading “change talk” (statements supportive of positive behavior change) during exposure to marijuana cues activated brain areas related to response inhibition (e.g., inferior frontal gyrus), and that greater activation in these regions was associated with better 1-month outcomes (Feldstein Ewing et al., 2013). The potential effect of motivational factors in enhancing inhibitory control suggest, for example, that proximal reminders of incentive structure in a contingency management intervention (Stanger and Budney, 2010) or booster motivational interview sessions could help to prime inhibitory control among SUD youth. Study limitations warrant comment. Generalizability of results is limited to youth recruited from community-based outpatient substance use treatment, most of whom were male and White, and primarily in treatment for marijuana use. This preliminary study analyzed a small sample of youth in substance use treatment. The small sample size and limited number of females precluded the ability to examine possible differences by sex. Although moderate to large effects were detected in hypothesized directions, and analyses included covariates, results need to be interpreted in the context of small sample size. Further, a relatively large number of ROIs was tested, and although false discovery rate was considered, replication is needed. Although both marijuana frequency and abuse/dependence symptom count declined over follow-up, only the reduction in marijuana symptom count was statistically significant, which may reflect limited sample size. However, similar results regarding alcohol and marijuana outcomes have been obtained in other research on adolescent treatment outcomes (Arias et al., 2014). Self-report of substance use and substance-related problems may be subject to bias, and biochemical verification of substance use was not conducted, although procedures to maximize validity (e.g., assurance of confidentiality) were used. fMRI data were not collected prior to initiating treatment, such that cognitive functioning at the time of the scan, which was associated with treatment outcome, could reflect, for example, effects of treatment or abstinence from substance use.
Conclusions This preliminary study identified a potential neurobiological marker that was associated with adolescent substance use treatment outcome. As a next step, research in a larger adolescent sample that examines the temporal ordering of regional activation (e.g., reward-related ROIs influencing oculomotor control regions) is needed to test a mechanistic model by which incentives and other motivational factors (e.g., change talk) acutely enhance cognitive control, which could ultimately inform the development of neuroscience-informed interventions that aim to strengthen cognitive control. Further research is needed to probe the use of adolescent sensitivity to reward (bottom-up processing) to prime or enhance top-down cognitive control over behavior to improve youth treatment outcomes.
Conflict of interest
Acknowledgements Support for the conduct of the research and preparation of the manuscript was provided by funding from the National Institute on Alcohol Abuse and Alcoholism and National Institute on Drug Abuse (R01 AA014357, R21 AA016272, R21 AA017128, K02 AA018195).