Graduate School of Information Science, Nara Institute of Science and Technology, Japan.
Neuroimage. 2010 Mar;50(1):314-22. doi: 10.1016/j.neuroimage.2009.12.017. Epub 2009 Dec 11.
Most real-world decision-making problems involve consideration of numerous possible actions, and it is often impossible to evaluate all of them before settling on preferred strategy. In such situations, humans might explore actions more efficiently by searching only the most likely subspace of the whole action space. To study how the brain solves such action selection problems, we designed a Multi Feature Sorting Task in which the task rules defining an optimal action have a hierarchical structure and studied concurrent brain activity using it. The task consisted of two kinds of rule switches: a higher-order switch to search for a rule across different subspaces and a lower-order switch to change a rule within the same subspace. The results revealed that the left dorsolateral prefrontal cortex (DLPFC) was more active in the higher-order switching, and the right fronto-polar cortex (FPC) was significantly activated with the lower-order switching. We discuss a possible functional model in the prefrontal cortex where the left DLPFC encodes the hierarchical organization of behaviours and the right FPC maintains and updates multiple behavioural. This interpretation is highly consistent with the previous findings and current theories of hierarchical organization in the prefrontal functional network.
大多数现实世界的决策问题都涉及到对多种可能行动的考虑，而在确定首选策略之前，通常不可能对所有行动进行评估。在这种情况下，人类可能会通过只搜索整个行动空间中最可能的子空间来更有效地探索行动。为了研究大脑如何解决这种行动选择问题，我们设计了一个多特征分类任务，其中定义最优行动的任务规则具有层次结构，并使用它研究并发的大脑活动。该任务包括两种规则切换：一种是在不同子空间中搜索规则的高阶切换，另一种是在同一子空间中改变规则的低阶切换。结果表明，左侧背外侧前额叶皮层（DLPFC）在高阶切换中更为活跃，右侧额极皮层（FPC）在低阶切换中显著激活。我们讨论了前额叶皮层中的一种可能的功能模型，其中左侧 DLPFC 编码行为的层次结构，右侧 FPC 维持和更新多个行为。这种解释与之前的发现和当前的前额叶功能网络中层次组织的理论高度一致。
