Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Proc Natl Acad Sci U S A. 2011 Aug 2;108(31):E402-9. doi: 10.1073/pnas.1100225108. Epub 2011 Jul 18.
Effective exploratory behaviors involve continuous updating of sensory sampling to optimize the efficacy of information gathering. Despite some work on this issue in animals, little information exists regarding the cognitive or neural mechanisms for this sort of behavioral optimization in humans. Here we examined a visual exploration phenomenon that occurred when human subjects studying an array of objects spontaneously looked "backward" in their scanning paths to view recently seen objects again. This "spontaneous revisitation" of recently viewed objects was associated with enhanced hippocampal activity and superior subsequent memory performance in healthy participants, but occurred only rarely in amnesic patients with severe damage to the hippocampus. These findings demonstrate the necessity of the hippocampus not just in the aspects of long-term memory with which it has been associated previously, but also in the short-term adaptive control of behavior. Functional neuroimaging showed hippocampal engagement occurring in conjunction with frontocerebellar circuits, thereby revealing some of the larger brain circuitry essential for the strategic deployment of information-seeking behaviors that optimize learning.
有效的探索性行为涉及到对感觉采样的持续更新，以优化信息收集的效果。尽管在动物身上已经做了一些关于这个问题的工作，但关于人类这种行为优化的认知或神经机制的信息却很少。在这里，我们研究了一种视觉探索现象，即当研究一系列物体的人类受试者在扫描路径中自发地“向后看”以再次查看最近看到的物体时，就会出现这种现象。在健康参与者中，这种对最近观看过的物体的“自发重访”与海马体活动增强和随后的记忆表现更好相关，但在海马体严重受损的健忘症患者中，这种现象很少发生。这些发现表明，海马体不仅在之前与之相关的长期记忆方面是必要的，而且在行为的短期自适应控制方面也是必要的。功能神经影像学显示，海马体的参与与额顶叶小脑回路同时发生，从而揭示了一些对于优化学习的信息寻求行为的战略部署至关重要的更大的大脑回路。
