Brain and Mind Institute, University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, N6A 5C1, Canada.
Hum Brain Mapp. 2017 Dec;38(12):6133-6156. doi: 10.1002/hbm.23817. Epub 2017 Sep 25.
We investigated a controversy regarding the role of the dorsal striatum (DS) in deliberate decision-making versus late-stage, stimulus-response learning to the point of automatization. Participants learned to associate abstract images with right or left button presses explicitly before strengthening these associations through stimulus-response trials with (i.e., Session 1) and without (i.e., Session 2) feedback. In Session 1, trials were divided into response-selection and feedback events to separately assess decision versus learning processes. Session 3 evaluated stimulus-response automaticity using a location Stroop task. DS activity correlated with response-selection and not feedback events in Phase 1 (i.e., Blocks 1-3), Session 1. Longer response times (RTs), lower accuracy, and greater intertrial variability characterized Phase 1, suggesting deliberation. DS activity extinguished in Phase 2 (i.e., Blocks 4-12), Session 1, once RTs, response variability, and accuracy stabilized, though stimulus-response automatization continued. This was signaled by persisting improvements in RT and accuracy into Session 2. Distraction between Sessions 1 and 2 briefly reintroduced response uncertainty, and correspondingly, significant DS activity reappeared in Block 1 of Session 2 only. Once stimulus-response associations were again refamiliarized and deliberation unnecessary, DS activation disappeared for Blocks 2-8, Session 2. Interference from previously learned right or left button responses with incongruent location judgments in a location Stroop task provided evidence that automaticity of stimulus-specific button-press responses had developed by the end of Session 2. These results suggest that DS mediates decision making and not late-stage learning, reconciling two, independently evolving and well-supported literatures that implicate DS in different cognitive functions. Hum Brain Mapp 38:6133-6156, 2017. © 2017 Wiley Periodicals, Inc.
我们研究了背侧纹状体（DS）在刻意决策与后期、刺激-反应学习达到自动化阶段的作用的争议。参与者在强化这些关联之前，通过带有（即第 1 会话）和不带有（即第 2 会话）反馈的刺激-反应试验，明确地学会将抽象图像与右或左按钮按下联系起来。在第 1 会话中，试验分为反应选择和反馈事件，以分别评估决策与学习过程。第 3 会话使用位置 Stroop 任务评估刺激-反应的自动性。DS 活动与第 1 会话的第 1 阶段（即第 1 至第 3 块）的反应选择而不是反馈事件相关，第 1 会话的第 1 阶段的特征是较长的反应时间（RT）、较低的准确性和更大的试验间变异性，这表明进行了深思熟虑。一旦 RT、反应变异性和准确性稳定下来，第 1 会话的第 2 阶段（即第 4-12 块）DS 活动就会消失，尽管刺激-反应的自动化仍在继续。这表现在第 2 会话中 RT 和准确性的持续提高。第 1 会话和第 2 会话之间的分心短暂地重新引入了反应的不确定性，相应地，第 2 会话第 1 块中仅出现了显著的 DS 活动。一旦再次熟悉了刺激-反应的关联，并且不需要进行深思熟虑，DS 激活在第 2 会话的第 2-8 块中就会消失。在位置 Stroop 任务中，先前学习的右或左按钮响应与不一致的位置判断之间的干扰提供了证据，表明刺激特异性按钮按下反应的自动性在第 2 会话结束时已经发展起来。这些结果表明，DS 介导决策而不是后期学习，调和了两种独立发展且得到充分支持的文献，这两种文献将 DS 与不同的认知功能联系起来。人类大脑映射 38：6133-6156，2017。© 2017 年 Wiley Periodicals，Inc.
