Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK; Centre for Cognitive and Neural Systems, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, 1 George Square, Edinburgh EH8 9JZ, UK.
Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK; Centre for Cognitive and Neural Systems, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, 1 George Square, Edinburgh EH8 9JZ, UK; University College London, Institute of Behavioural Neuroscience, Department of Experimental Psychology, London, UK.
Curr Biol. 2017 Sep 11;27(17):2706-2712.e2. doi: 10.1016/j.cub.2017.07.071. Epub 2017 Aug 31.
A central tenet of systems neuroscience is that the mammalian hippocampus provides a cognitive map of the environment. This view is supported by the finding of place cells, neurons whose firing is tuned to specific locations in an animal's environment, within this brain region. Recent work, however, has shown that these cells repeat their firing fields across visually identical maze compartments [1, 2]. This repetition is not observed if these compartments face different directions, suggesting that place cells use a directional input to differentiate otherwise similar local environments [3, 4]. A clear candidate for this input is the head direction cell system. To test this, we disrupted the head direction cell system by lesioning the lateral mammillary nuclei and then recorded place cells as rats explored multiple, connected compartments, oriented in the same or in different directions. As shown previously, we found that place cells in control animals exhibited repeated fields in compartments arranged in parallel, but not in compartments facing different directions. In contrast, the place cells of animals with lesions of the head direction cell system exhibited repeating fields in both conditions. Thus, directional information provided by the head direction cell system appears essential for the angular disambiguation by place cells of visually identical compartments.
系统神经科学的一个中心原则是，哺乳动物的海马体为环境提供了认知地图。这一观点得到了在该脑区发现的位置细胞的支持，位置细胞的发射与动物环境中的特定位置相匹配。然而，最近的研究表明，这些细胞在视觉上相同的迷宫隔室中重复其发射场[1,2]。如果这些隔室面向不同的方向，则不会观察到这种重复，这表明位置细胞使用方向输入来区分否则相似的局部环境[3,4]。头方向细胞系统是这种输入的一个明显候选者。为了验证这一点，我们通过破坏外侧乳状核来破坏头方向细胞系统，然后记录大鼠在探索多个连接的隔室时的位置细胞，这些隔室的方向相同或不同。如前所述，我们发现对照组动物的位置细胞在平行排列的隔室中表现出重复的场，但在面向不同方向的隔室中则没有。相比之下，头方向细胞系统受损的动物的位置细胞在这两种情况下都表现出重复的场。因此，头方向细胞系统提供的方向信息似乎是位置细胞对视觉上相同的隔室进行角度分辨所必需的。
