Hok Vincent, Lenck-Santini Pierre-Pascal, Roux Sébastien, Save Etienne, Muller Robert U, Poucet Bruno
Laboratory of Neurobiology and Cognition, Centre National de la Recherche Scientifique (CNRS)-Université de Provence, 13331 Marseille Cedex 03, France.
J Neurosci. 2007 Jan 17;27(3):472-82. doi: 10.1523/JNEUROSCI.2864-06.2007.
Place cells are hippocampal neurons whose discharge is strongly related to a rat's location in its environment. The existence of place cells has led to the proposal that they are part of an integrated neural system dedicated to spatial navigation, an idea supported by the discovery of strong relationships between place cell activity and spatial problem solving. To further understand such relationships, we examined the discharge of place cells recorded while rats solved a place navigation task. We report that, in addition to having widely distributed firing fields, place cells also discharge selectively while the hungry rat waits in an unmarked goal location to release a food pellet. Such firing is not duplicated in other locations outside the main firing field even when the rat's behavior is constrained to be extremely similar to the behavior at the goal. We therefore propose that place cells provide both a geometric representation of the current environment and a reflection of the rat's expectancy that it is located correctly at the goal. This on-line feedback about a critical aspect of navigational performance is proposed to be signaled by the synchronous activity of the large fraction of place cells active at the goal. In combination with other (prefrontal) cells that provide coarse encoding of goal location, hippocampal place cells may therefore participate in a neural network allowing the rat to plan accurate trajectories in space.
位置细胞是海马体神经元，其放电与大鼠在环境中的位置密切相关。位置细胞的存在促使人们提出，它们是专门用于空间导航的整合神经系统的一部分，这一观点得到了位置细胞活动与空间问题解决之间紧密关系的发现的支持。为了进一步理解这种关系，我们研究了大鼠在解决位置导航任务时记录的位置细胞的放电情况。我们报告称，除了具有广泛分布的放电野之外，当饥饿的大鼠在无标记的目标位置等待释放食物颗粒时，位置细胞也会选择性地放电。即使大鼠的行为被限制为与在目标位置时的行为极其相似，在主要放电野之外的其他位置也不会出现这种放电情况。因此，我们提出位置细胞既提供当前环境的几何表示，也反映大鼠对其正确位于目标位置的预期。这种关于导航性能关键方面的在线反馈被认为是由在目标位置活跃的大部分位置细胞的同步活动发出信号的。与提供目标位置粗略编码的其他（前额叶）细胞相结合，海马体位置细胞因此可能参与一个神经网络，使大鼠能够在空间中规划准确的轨迹。
