Pleger Burkhard, Ruff Christian C, Blankenburg Felix, Klöppel Stefan, Driver Jon, Dolan Raymond J
Wellcome Trust Centre for Neuroimaging at UCL, London, United Kingdom.
PLoS Biol. 2009 Jul;7(7):e1000164. doi: 10.1371/journal.pbio.1000164. Epub 2009 Jul 28.
Reward-related dopaminergic influences on learning and overt behaviour are well established, but any influence on sensory decision-making is largely unknown. We used functional magnetic resonance imaging (fMRI) while participants judged electric somatosensory stimuli on one hand or other, before being rewarded for correct performance at trial end via a visual signal, at one of four anticipated financial levels. Prior to the procedure, participants received either placebo (saline), a dopamine agonist (levodopa), or an antagonist (haloperidol).
higher anticipated reward improved tactile decisions. Visually signalled reward reactivated primary somatosensory cortex for the judged hand, more strongly for higher reward. After receiving a higher reward on one trial, somatosensory activations and decisions were enhanced on the next trial. These behavioural and neural effects were all enhanced by levodopa and attenuated by haloperidol, indicating dopaminergic dependency. Dopaminergic reward-related influences extend even to early somatosensory cortex and sensory decision-making.
与奖励相关的多巴胺能对学习和明显行为的影响已得到充分证实，但对感觉决策的任何影响在很大程度上尚不清楚。我们使用功能磁共振成像（fMRI），让参与者判断是一只手还是另一只手受到电躯体感觉刺激，在试验结束时通过视觉信号在四个预期金钱水平之一对正确表现给予奖励之前进行判断。在该程序之前，参与者接受安慰剂（生理盐水）、多巴胺激动剂（左旋多巴）或拮抗剂（氟哌啶醇）。
更高的预期奖励改善了触觉决策。视觉信号奖励重新激活了被判断手的初级躯体感觉皮层，奖励越高激活越强。在一次试验中获得更高奖励后，下一次试验中躯体感觉激活和决策增强。这些行为和神经效应均被左旋多巴增强，被氟哌啶醇减弱，表明存在多巴胺能依赖性。与多巴胺能奖励相关的影响甚至延伸到早期躯体感觉皮层和感觉决策。
