Drug abuse liability is associated with higher reward-sensitivity: An fMRI study using the Monetary Incentive Delay task C. Corbly, T. Kelly, Y. Jiang, D. Lee, S. Kiser and J. Joseph Anatomy & Neurobiology, University of Kentucky Chandler Medical Center, Lexington, KY USA METHOD Monetary Incentive Delay Task (Bjork et al. 2004) involves responding to a target within a limited time window in order to receive monetary rewards or avoid monetary losses RESULTSOBJECTIVES Sensation seeking (SS) is a biologically based personality trait marked by a tendency to seek out and engage in novel and varied experiences to maintain an optimal level of arousal -- even if those experiences involve significant risk (Zuckerman, 1994; 2005) High sensation seekers are vulnerable to drug abuse and other risky behaviors Our goal is to examine the contribution of reward seeking and impulsivity dimensions of the SS scale to differences in behavior and brain activation using the MID task and fMRI 16 Subjects : 9 Low Risk 7 High Risk bottom or top quartile of the SS scale respectively CONCLUSIONS High-risk individuals were more motivated to respond within the allotted time window to receive rewards or avoid losses than were low-risk individuals The Ventral Striatum is associated with reward behaviors however this region seems to be unaffected by personality type and more by High Reward R Ant Cingulate is associated with anticipation of tasks & motivation. It is also strongly associated with rewards & losses. The High-risk individuals show more motivation for the High Value items behaviorally. This may be driven by the R Ant Cingulate region. REFERENCES Bjork, J. M., Knutson, B., Fong, G., Caggiano, D., Bennett, S., & Hommer, D. W. (2004). Incentive-elicited brain activation in adolescents: Similarities and differences from young adults. Journal of Neuroscience, 24, Zuckerman, M. (1994). Behavioral expressions and biosocial bases of sensation seeking. New York: Cambridge University Press. Zuckerman, M. (2005). The neurobiology of impulsive sensation seeking: Genetics, brain physiology, biochemistry, and neurology. In C. Stough (Ed.), Neurobiology of exceptionality (pp ). New York: Kluwer Academic / Plenum Publishers. ACKNOWLEDGEMENT S This research was supported by NICHD R01 HD052724, COBRE P20 RR CDART P50 DA00312 Performance on the MID task for individuals classified as high-risk versus low-risk for drug abuse vulnerability Brain activation (p <.0005) in the right anterior cingulate cortex and the bilateral ventral striatum that was associated with greater activation for high positive or negative incentive values The parameter estimate reflects fMRI signal greater for each incentive value relative to visual fixation. fMRI signal is plotted as a function of risk status Time Cue Win $.50 or $5 Lose $.50 or $5 Neutral $0 1500ms Target (Subject Response) Acc constrained to 66% 200 – 360ms Feedback  Correct  Incorrect Total 1500ms filler Variable Trial Length  Total $4.50 Positive Cue Reward  +  Total $  +  Total $0 Negative Cue Loss Avoidance Neutral Cue Neutral Outcome Low risk High risk Incentive value ($) R ventral striatum Low risk High risk Incentive value ($) L ventral. striatum Low risk High risk Incentive value ($) Low risk High risk Incentive value ($) R ant. cingulate Behavioral Results Three Trial Types Reward Loss Avoidance Neutral