Archive for the ‘Nucleus accumbens / ventral striatum’ Category

How desirable and pleasurable are social relationships? It depends on who you ask…

February 1, 2013

Summary

There are individual differences in how much people desire and seek out social interactions, and how comfortable people feel in getting emotionally close to others.  Are these individual differences in behavior related to differences in brain function?  Vrticka (2012) argues that reduced interest in social interaction and close relationships is associated with reduced activation of brain reward circuits in response to social stimuli.

More details

Most of us desire social interactions and take pleasure in close relationships with at least a small number of other people.  On the other hand, most of us also need some personal space and independence.  The preferred balance of interpersonal closeness vs. space varies from individual to individual.    A recent review by Vrticka (2012) addresses potential neural mechanisms underlying these individual differences.  Vrticka argues that, in each of us, there is a “‘push-pull’ mechanism between two opposing emotional neural circuits”(Vrticka (2012)—one of which mediates social approach/reward, and the other which mediates social avoidance/aversion (Porges et al 2003).  Vrticka writes that a likely candidate for the neural circuits that mediate social reward, e.g. the pleasures of positive interactions with a friend  or loved one, are the well-characterized brain reward circuits–including dopaminergic neurons that project from the ventral tegmental area (VTA) to the ventral striatum (VS, including the nucleus accumbens) and medial prefrontal cortex (mPFC), which mediate many different types of pleasurable and rewarding stimuli, including food and drugs of abuse.

To support the hypothesis that these neural circuits mediate social rewards, Vrticka cites an article by Fareri et al (2012) that finds greater activation of the VS and mPFC when money rewards were shared with a friend than when they were shared with an unfamiliar person.   In addition, Vrticka (2012) argues that individual differences in attachment style—a person’s relatively stable patterns of expectations, emotions, and behaviors in close relationships—maybe mediated by differences in the functioning of these brain reward circuits.  In a previous study, Vrticka and coworkers (2008) found that an “avoidant” attachment style—characterized by a preference for interpersonal distance and discomfort in getting too emotionally close to others—was associated with reduced activation of the VS in response to positive social feedback on performance in a game, but no alteration in VS responsiveness to nonsocial successes (winning the game).  As Vrticka (2012) points out, further studies of the functioning of these reward circuits seem warranted, not only for better understanding individuals differences in social reward, but also to better understand psychiatric and neurodevelopmental disorders characterized by reduced social interaction.  For example, there are recent reports of alterations in the function of brain reward circuitry in autism spectrum disorders (Kohls et al 2012a; Kohls 2012b).

References

Fareri DS, Niznikiewicz MA, Lee VK, Delgado MR (2012) Social network modulation of reward-related signals. The Journal of Neuroscience 32(26):9045-9052.

Kohls G, Chevallier C, Troiani V, Schultz RT (2012a) Social ‘wanting’ dysfunction in autism:  neurobiological underpinnings and treatment implications.  J Neurodev Disord 4(1):10.

Kohls G, Schulte-Rüther M, Nehrkorn B, Müller K, Fink GR, Kamp-Becker I, Herpertz-Dahlmann B, Schultz RT, Konrad K (2012b) Reward system dysfunction in autism spectrum disorders.  Soc Cogn Affect Neurosci, in press.

Porges SW (2003) Social engagement and attachment:  a phylogenetic perspective. Ann NY Acad Sci 1008(Dec):31-47.

Vrticka P (2012) Interpersonal closeness and social reward processing.  The Journal of Neuroscience 32(37):12649-12650.

Vrticka P, Andersson F, Grandjean D, Sander D, Vuilleumier P (2008) Individual attachment style modulates human amygdala and striatum activation during social appraisal.  PLoS One 3:e2868.

Vrticka P and Vuilleumier P (2012) Neuroscience of human social interactions and adult attachment style.  Front Hum Neurosci 6:212.

©2011-2013 Edward S. Brodkin.  All Rights Reserved

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