Bi-directional effect of increasing doses of baclofen on reinforcement learning

Article Article scientifique Article Bi-directional effect of increasing doses of baclofen on reinforcement learning eng 2011 author Terrier Jean 536564 author Ort Andrés 597523 author Yvon Cédric Marcel 105566 author Saj Arnaud 666496 author Vuilleumier Patrik 0000-0002-8198-9214 134853 author Luescher Christian 132337 40 10.3389/fnbeh.2011.00040 21811448 1662-5153 In rodents as well as in humans, efficient reinforcement learning depends on dopamine (DA) released from ventral tegmental area (VTA) neurons. It has been shown that in brain slices of mice, GABA(B)-receptor agonists at low concentrations increase the firing frequency of VTA-DA neurons, while high concentrations reduce the firing frequency. It remains however elusive whether baclofen can modulate reinforcement learning in humans. Here, in a double-blind study in 34 healthy human volunteers, we tested the effects of a low and a high concentration of oral baclofen, a high affinity GABA(B)-receptor agonist, in a gambling task associated with monetary reward. A low (20 mg) dose of baclofen increased the efficiency of reward-associated learning but had no effect on the avoidance of monetary loss. A high (50 mg) dose of baclofen on the other hand did not affect the learning curve. At the end of the task, subjects who received 20 mg baclofen p.o. were more accurate in choosing the symbol linked to the highest probability of earning money compared to the control group (89.55 ± 1.39 vs. 81.07 ± 1.55%, p = 0.002). Our results support a model where baclofen, at low concentrations, causes a disinhibition of DA neurons, increases DA levels and thus facilitates reinforcement learning. Dewey 616.8 Dewey 128.37 15 Centre interfacultaire en sciences affectives 0D8 53 Département de neurosciences fondamentales 21A false 1241 Affective sciences 428 Mécanismes cérébraux du comportement et des fonctions cognitives 701 Frontiers in behavioral neuroscience 5 aa18e726-a3af-4b82-98e4-d75d98be0e57 Article (Published version) Public terrier_frontiersBN2011.pdf 1139301 application/pdf openAccess Centres et instituts / Centre interfacultaire en sciences affectives Faculté de médecine / Section de médecine fondamentale / Département de neurosciences fondamentales

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Bi-directional effect of increasing doses of baclofen on reinforcement learning	Frontiers in behavioral neuroscience			2011	724	269

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