Imaging Research Center, The University of Texas at Austin Austin, TX, USA ; Precision and Intelligence Laboratory, Tokyo Institute of Technology Yokohama, Japan.
Department of Psychology, University of California Los Angeles Los Angeles, USA.
Front Hum Neurosci. 2014 May 22;8:339. doi: 10.3389/fnhum.2014.00339. eCollection 2014.
Learning novel skills involves reorganization and optimization of cognitive processing involving a broad network of brain regions. Previous work has shown asymmetric costs of switching to a well-trained task vs. a poorly-trained task, but the neural basis of these differential switch costs is unclear. The current study examined the neural signature of task switching in the context of acquisition of new skill. Human participants alternated randomly between a novel visual task (mirror-reversed word reading) and a highly practiced one (plain word reading), allowing the isolation of task switching and skill set maintenance. Two scan sessions were separated by 2 weeks, with behavioral training on the mirror reading task in between the two sessions. Broad cortical regions, including bilateral prefrontal, parietal, and extrastriate cortices, showed decreased activity associated with learning of the mirror reading skill. In contrast, learning to switch to the novel skill was associated with decreased activity in a focal subcortical region in the dorsal striatum. Switching to the highly practiced task was associated with a non-overlapping set of regions, suggesting substantial differences in the neural substrates of switching as a function of task skill. Searchlight multivariate pattern analysis also revealed that learning was associated with decreased pattern information for mirror vs. plain reading tasks in fronto-parietal regions. Inferior frontal junction and posterior parietal cortex showed a joint effect of univariate activation and pattern information. These results suggest distinct learning mechanisms task performance and executive control as a function of learning.
学习新技能涉及到认知处理的重新组织和优化，涉及到广泛的大脑区域网络。先前的工作表明，在切换到训练有素的任务与训练不足的任务时，存在不对称的切换成本，但这些差异切换成本的神经基础尚不清楚。本研究在获得新技能的背景下，考察了任务切换的神经特征。人类参与者在一项新的视觉任务（镜像反转单词阅读）和一项高度熟练的任务（普通单词阅读）之间随机交替，从而可以分离任务切换和技能集维持。两个扫描会话之间间隔 2 周，在此期间对镜像阅读任务进行行为训练。广泛的皮质区域，包括双侧前额叶、顶叶和外纹状体皮质，表现出与镜像阅读技能学习相关的活动减少。相比之下，学习切换到新技能与背侧纹状体中的一个焦点皮质下区域的活动减少有关。切换到高度熟练的任务与不重叠的一组区域有关，这表明作为任务技能的函数，切换的神经基质存在实质性差异。搜索灯多元模式分析还表明，在额顶叶区域，学习与镜像阅读任务相比，模式信息减少。额下回和后顶叶皮层表现出单变量激活和模式信息的联合效应。这些结果表明，学习机制与执行控制在功能上存在明显的差异，这取决于学习。
