Motivational saliency signal in the ventral striatum is modulated by genetic variation in the ARC gene region

Wednesday, October 26, 2011 — Poster Session IV
2:00 p.m. – 4:00 p.m.	Natcher Conference Center	NIMH	NEURO/BEHAV/SENSYS-8

Authors

• SA Colalillo
• DN Blitzer
• JW Barter
• MR Haynes
• KH Wang
• DR Weinberger
• CF Zink

Abstract

Using fMRI, brain activation in the ventral striatum (vSTR) has been associated with the motivational value of the cues predicting reward. In the current “imaging genetics” study, we used an adapted Monetary Incentive Delay task during fMRI to investigate the influence of dopaminergic and glutamatergic genetic variations on this motivational saliency signal. In each trial, subjects responded, via single button press, to a visually presented target. Just prior to target appearance, participants were shown one of two cues predicting potential reward: one associated with relatively higher motivational value (a shorter response window) and one associated with relatively lower motivational value (a longer response window). A control cue was not predictive of a reward or difficulty. Using a regression analysis, we found that a single nucleotide polymorphism downstream, yet in close proximity, to the ARC gene (rs9324593), predicted the vSTR response to motivational salience, with the G allele being associated with significantly greater vSTR BOLD signal. While the effect of the rs9324593 SNP on ARC protein is still under investigation, these results highlight a genetic variation with potential functionality in the glutamatergic system, which may account for individual differences in the neural coding of motivational value.

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