Computational, Cognitive and Clinical Neuroscience Laboratory, Department of Medicine, Imperial College London, London W12 0NN, UK.
Computational, Cognitive and Clinical Neuroscience Laboratory, Department of Medicine, Imperial College London, London W12 0NN, UK.
Neuroimage. 2019 May 15;192:88-100. doi: 10.1016/j.neuroimage.2019.03.002. Epub 2019 Mar 6.
Diverse cortical networks and striatal brain regions are implicated in instruction-based learning (IBL); however, their distinct contributions remain unclear. We use a modified fMRI paradigm to test two hypotheses regarding the brain mechanisms that underlie IBL. One hypothesis proposes that anterior caudate and frontoparietal regions transiently co-activate when new rules are being bound in working memory. The other proposes that they mediate the application of the rules at different stages of the consolidation process. In accordance with the former hypothesis, we report strong activation peaks within and increased connectivity between anterior caudate and frontoparietal regions when rule-instruction slides are presented. However, similar effects occur throughout a broader set of cortical and sub-cortical regions, indicating a metabolically costly reconfiguration of the global brain state. The distinct functional roles of cingulo-opercular, frontoparietal and default-mode networks are apparent from their activation throughout, early and late in the practice phase respectively. Furthermore, there is tentative evidence of a peak in anterior caudate activity mid-way through the practice stage. These results demonstrate how performance of the same simple task involves a steadily shifting balance of brain systems as learning progresses. They also highlight the importance of distinguishing between regional specialisation and global dynamics when studying the network mechanisms that underlie cognition and learning.
不同的皮质网络和纹状体脑区与基于指令的学习（IBL）有关；然而，它们的具体贡献仍不清楚。我们使用改良的 fMRI 范式来检验两个关于基于指令学习的大脑机制的假设。一个假设提出，在工作记忆中绑定新规则时，前尾状核和额顶叶区域会短暂地共同激活。另一个假设提出，它们在巩固过程的不同阶段中介新规则的应用。根据前一个假设，当呈现规则指令幻灯片时，我们报告了前尾状核和额顶叶区域内的强烈激活峰值和增加的连接。然而，类似的效应也发生在更广泛的皮质和皮质下区域，表明全局大脑状态的代谢成本重新配置。扣带-顶叶、额顶叶和默认模式网络的独特功能作用，从它们在实践阶段的整个过程、早期和晚期的激活中可以明显看出。此外，在前尾状核活动的中期有一个峰值的初步证据。这些结果表明，即使执行相同的简单任务，随着学习的进展，大脑系统的平衡也会不断变化。它们还强调了在研究认知和学习的网络机制时，区分区域专业化和全局动态的重要性。
