Drug abuse liability is associated with higher reward-sensitivity:

1. R ant. cingulate High risk Low risk -5 -.5 0 .5 5 Incentive value ($) L ventral. striatum R ventral striatum Low risk Low risk High risk High risk + -5 -.5 0 .5 5 Incentive value ($) Incentive value ($) + 5 + J + a Total $4.50 Positive Cue Reward + - 5 + + - 0 N -5 -.5 0 .5 5 + + r Total $0 N Negative Cue Loss Avoidance + r Total $1.50 Drug abuse liability is associated with higher reward-sensitivity: An fMRI study using the Monetary Incentive Delay task C. Corbly, T. Kelly, Y. Jiang, D. Lee, S. Kiser and J. Joseph Anatomy & Neurobiology, University of Kentucky Chandler Medical Center, Lexington, KY USA • OBJECTIVES • Sensation seeking (SS) is a biologically based personality trait marked by a tendency to seek out and engage in novel and varied experiences to maintain an optimal level of arousal -- even if those experiences involve significant risk (Zuckerman, 1994; 2005) • High sensation seekers are vulnerable to drug abuse and other risky behaviors • Our goal is to examine the contribution of reward seeking and impulsivity dimensions of the SS scale to differences in behavior and brain activation using the MID task and fMRI • 16 Subjects : 9 Low Risk 7 High Risk bottom or top quartile of the SS scale respectively RESULTS • CONCLUSIONS • High-risk individuals were more motivated to respond within the allotted time window to receive rewards or avoid losses than were low-risk individuals • The Ventral Striatum is associated with reward behaviors however this region seems to be unaffected by personality type and more by High Reward • R Ant Cingulate is associated with anticipation of tasks & motivation. It is also strongly associated with rewards & losses. The High-risk individuals show more motivation for the High Value items behaviorally. • This may be driven by the R Ant Cingulate region. Behavioral Results Low risk High risk -5 -.5 0 .5 5 Incentive value ($) 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 • 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, 1793-1802. • 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. 31-52). New York: Kluwer Academic / Plenum Publishers. Cue Win $.50 or $5 Lose $.50 or $5 Neutral $0 Target (Subject Response) Acc constrained to 66% Feedback a Correct rIncorrect Total filler filler 1500ms 200 – 360ms 1500ms Time • Three Trial Types • Reward • Loss Avoidance • Neutral Variable Trial Length • 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 ACKNOWLEDGEMENTS This research was supported by NICHD R01 HD052724, COBRE P20 RR-15592 CDART P50 DA00312 Neutral Cue Neutral Outcome