Publicaciones científicas

Dopaminergic modulation of the trade-off between probability and time in economic decision-making

09-mar-2015 | Revista: European Neuropsychopharmacology

Arrondo G(1), Aznárez-Sanado M(2), Fernández-Seara MA(2), Goñi J(2), Loayza FR(2), Salamon-Klobut E(3), Heukamp FH(3), Pastor MA(4).

(1) Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; Managerial Decision Sciences, IESE Business School, University of Navarra, 08034 Barcelona, Spain; Psychiatry Department, University of Cambridge, United Kingdom.
(2) Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain.
(3) Managerial Decision Sciences, IESE Business School, University of Navarra, 08034 Barcelona, Spain.
(4) Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain.


Resumen

Studies on animals and humans have demonstrated the importance of dopamine in modulating decision-making processes. In this work, we have tested dopaminergic modulation of economic decision-making and its neural correlates by administering either placebo or metoclopramide, a dopamine D2-receptor antagonist, to healthy subjects, during a functional MRI study.

The decision-making task combined probability and time delay with a fixed monetary reward. For individual behavioral characterization, we used the Probability Time Trade-off (PTT) economic model, which integrates the traditional trade-offs of reward magnitude-time and reward magnitude-probability into a single measurement, thereby quantifying the subjective value of a delayed and probabilistic outcome. A regression analysis between BOLD signal and the PTT model index permitted to identify the neural substrate encoding the subjective reward-value.

Behaviorally, medication reduced the rate of temporal discounting over probability, reflected in medicated subjects being more prone to postpone the reward in order to increase the outcome probability. In addition, medicated subjects showed less activity during the task in the postcentral gyrus as well as frontomedian areas, whereas there were no differences in the ventromedial orbitofrontal cortex (VMOFC) between groups when coding the subjective value.

The present study demonstrates by means of behavior and imaging that dopamine modulation alters the probability-time trade-off in human economic decision-making.

CITA DEL ARTÍCULO European Neuropsychopharmacology (Impact Factor: 5.4). 06/2015; DOI: 10.1016/j.euroneuro.2015.02.011

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