Neurodevelopmental changes in social reinforcement processing: a functional MRI study.
Soonjo Hwang 1*, Harma Meffert 2, Michelle R. VanTieghem 3, Stuart F. White , 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 Psychiatry, 4Section on Affective Cognitive Neuroscience, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, 5University of California, Brain Research Institute
Received: March 30, 2017; Revised: August 10, 2017; Accepted: September 4, 2017; Published online: September 4, 2017.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: In the current study we investigated neurodevelopmental changes in response to social and non-social reinforcement.
Method: Fifty-three healthy participants including 16 early adolescents (age 10-15), 16 late adolescents (age 15-18), and 21 young adults (age 21-25) completed a social/non-social reward learning task while undergoing functional MRI. Participants responded to fractal image stimuli and received social or non-social reward/non-rewards according to their accuracy. ANOVAs were conducted on both the blood oxygen level dependent (BOLD) response data and the product of a context-dependent psychophysiological interaction (gPPI) analysis involving ventromedial prefrontal cortex (vmPFC) and bilateral insula cortices as seed regions.
Result: Early adolescents showed significantly increased activation in the amygdala and anterior insula cortex in response to non-social monetary rewards relative to both social reward/non-reward and monetary non-rewards compared to late adolescents and young adults. In addition, early adolescents showed significantly more positive connectivity between the vmPFC/bilateral insula cortices seeds and other regions implicated in reinforcement processing (the amygdala, posterior cingulate cortex, insula cortex, and lentiform nucleus) in response to non-reward and especially social non-reward, compared to late adolescents and young adults.
Conclusion: It appears that early adolescence may be marked by: (i) a selective increase in responsiveness to non-social, relative to social, rewards; and; (ii) enhanced, integrated functioning of reinforcement circuitry for non-reward, and in particular, with respect to posterior cingulate and insula cortices, for social non-reward.
Keywords: functional MRI, social reward, ventro-medial prefrontal cortex, amygdala, anterior insula, context-dependent psychophysiological interaction (gPPI)