Dysfunctional Social Reinforcement Processing in Disruptive Behavior Disorders: an fMRI study.
Soonjo Hwang 1*, Harma Meffert 2, Michelle R. VanTieghem 3, Stephen Sinclair 4, Susan Y Bookheimer 5, James Blair 2
1University of Nebraska Medical Center, Department of Psychiatry, 2Center for Neurobehavioral Research, Boys Town National Research Hospital, 3Columbia University, Department of Psychology, 4Section on Affective Cognitive Neuroscience, National Institute of Mental Health, 5University of California Los Angeles, Brain Research Institute
Received: July 14, 2017; Revised: November 11, 2017; Accepted: November 13, 2017; Published online: November 13, 2017.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: Prior fMRI work has revealed that children/adolescents with Disruptive Behavior Disorders (DBDs) show dysfunctional reward/non-reward processing of non-social reinforcements in the context of instrumental learning tasks. However, neural responsiveness to social reinforcements during instrumental learning, despite the importance of this for socialization, has not been previously investigated.
Method: 29 healthy children/adolescents and 19 children/adolescents with DBDs performed the social/non-social reinforcement learning task while undergoing fMRI. Participants responded to fractal image stimuli and received social and non-social rewards/non-rewards according to their accuracy.
Results: Children/adolescents with DBDs showed significantly reduced responses within caudate and posterior cingulate cortex (PCC) to financial rewards and social non-rewards (the distress of others). Connectivity analyses revealed that children/adolescents with DBDs showed decreased positive functional connectivity between ventral striatum (VST) and ventro-medial prefrontal cortex (vmPFC) seeds and lateral frontal cortex in response to reward relative to non-reward irrespective of its sociality. In addition, they showed decreased positive connectivity between the vmPFC seed and the amygdala in response to non-reward relative to reward.
Conclusion: These data indicate compromised reinforcement processing of both non-social rewards and social non-rewards (distress of others) in children/adolescents with DBDs within core regions for instrumental learning/reinforcement-based decision-making (caudate and PCC). In addition, children/adolescents with DBDs show dysfunctional interactions between VST and vmPFC and lateral frontal cortex in response to rewarded instrumental actions perhaps reflecting disruptions in attention to rewarded stimuli.
Keywords: Disruptive Behavior Disorder, Social reward, Ventral striatum, Posterior cingulate cortex, Ventro-medial prefrontal cortex