Montreal Neurological Institute, Cognitive Neuroscience Unit, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
Neuroimage. 2012 Nov 15;63(3):1078-90. doi: 10.1016/j.neuroimage.2012.06.023. Epub 2012 Jun 23.
The present functional magnetic resonance imaging (fMRI) experiment aims at clarifying the role of the rostral anterior cingulate cortex (rACC) in the evaluation of feedback in a deterministic environment. We tested, in particular, the response of the rACC to the detection of different types of feedback, and to varying levels of outcome expectancy. We used a problem-solving task in which subjects had to discover, in successive trials, which one of the four presented stimuli was associated with a positive feedback, the other ones being associated with error feedback. In this task, two periods alternated: 1. an exploratory period in which error feedback indicated to adapt the following response appropriately (and continue to explore), and first positive feedback indicated to change strategy (i.e. to shift from explorative to exploitative behavior), and 2. an exploitative period in which subjects had to repeat the correct choice. The rACC is recruited in the exploratory period during the analysis of both error and first correct positive feedback. In addition, the rACC activity was modulated by positive reward prediction error values (i.e. the difference between obtained and expected feedback). Altogether, these results reveal the critical role of the rACC in the evaluation of salient feedback for learning optimal strategies.
本功能磁共振成像（fMRI）实验旨在阐明额前扣带皮质（rACC）在确定性环境下反馈评估中的作用。我们特别测试了 rACC 对检测不同类型反馈和不同程度的结果预期的反应。我们使用了一个解决问题的任务，在这个任务中，受试者必须在连续的试验中发现四个呈现的刺激中的哪一个与正反馈相关，而其他的与错误反馈相关。在这个任务中，两个时期交替出现：1. 探索期，错误反馈表明要适当调整后续反应（并继续探索），而第一次正反馈表明要改变策略（即从探索性转向剥削性行为），2. 剥削期，受试者必须重复正确的选择。rACC 在分析错误和第一次正确的正反馈时都会在探索期被招募。此外，rACC 的活动还受到正奖励预测误差值（即实际反馈与预期反馈之间的差异）的调节。总的来说，这些结果揭示了 rACC 在评估对学习最佳策略有重要作用的显著反馈方面的关键作用。
