如今通过GPS系统，我们就能准确地找到自己所处的位置。那我们的大脑里是否也存在这样的系统来告诉我们所在的地点？

by 王璐璐 | 2015-07-07

GPS细胞——预知你的行为

如今通过GPS系统，我们就能准确地找到自己所处的位置。那我们的大脑里是否也存在这样的系统来告诉我们所在的地点？并且告诉我们如何能找到我们想去的地方的路线呢？2014年诺贝尔生理学或医学奖的获奖者John O’Keefe, May-Britt Moser 和Edvard I. Moser发现我们的大脑里存在着这样的“GPS”系统，使得我们能够定位自己所处的位置。其中这个系统的成分之一位置细胞（placecells）位于大脑的海马中，在实验中发现当大鼠身处某一特定位置时，该细胞就会被激活而处于活跃状态，而大鼠移动到其他位置时，另外一些神经细胞又会被激活。而另一种关键成分——网格细胞能够构建出坐标系，便于我们精确定位和查找路线。

在科幻和神话影视作品中，经常会出现这样一类人，他们能够预知其他人的行踪和即将发生的事情。那么既然我们的大脑里存在可以定位的“GPS”系统，我们能不能通过接入我们大脑中的定位信号来预知我们接下来想去的地方？HiroshiT. Ito, May-Britt Moser等研究人员在2015年5月Nature发表的一篇文章中给予了确切的回答。研究人员选取了从内侧前额叶皮质经由丘脑核到达海马这一信号通路，想探究这条通路是否是使得大脑能够编码我们计划从这个地方到另一个地方的定位机制。研究人员以大鼠为实验动物，在T形迷宫里对其进行训练，实验发现动物在走向不同的轨道时，其大脑特定神经元的放电强度是不同的。因此我们可以通过对特定神经元的放电强弱对动物的路线选择进行预测。

目前针对大脑的定位系统，科学家们还在不断的探索中，相信在不久的将来，我们对于“GPS”细胞会了解的更加深入，也能够启发更多的科学家们对我们的大脑研究得更加透彻和全面。

相关文献：

1、A prefrontal-thalamo-hippocampalcircuit for goal-directed spatial navigation.

原文摘要：Spatial navigation requires informationabout the relationship between current and future positions. The activity ofhippocampal neurons appears to reflect such a relationship, representing notonly instantaneous position but also the path towards a goal location. However,how the hippocampus obtains information about goal direction is poorlyunderstood. Here we report a prefrontal-thalamic neural circuit that isrequired for hippocampal representation of routes or trajectories through theenvironment. Trajectory-dependent firing was observed in medial prefrontalcortex, the nucleus reuniens of the thalamus, and the CA1 region of thehippocampus in rats. Lesioning or optogenetic silencing of the nucleus reunienssubstantially reduced trajectory-dependent CA1 firing. Trajectory-dependentactivity was almost absent in CA3, which does not receive nucleus reuniensinput. The data suggest that projections from medial prefrontal cortex, via thenucleus reuniens, are crucial for representation of the future path duringgoal-directed behaviour and point to the thalamus as a key node in networks forlong-range communication between cortical regions involved in navigation.

全文链接：http://www.nature.com/nature/journal/v522/n7554/pdf/nature14396.pdf

2、Place cells, grid cells, and the brain’s spatialrepresentation system.

原文摘要：More than three decades of research have demonstrated a rolefor hippocampal place cells in representation of the spatial environment in thebrain. New studies have shown that place cells are part of a broader circuitfor dynamic representation of self-location. A key component of this network isthe entorhinal grid cells, which, by virtue of their tessellating firingfields, may provide the elements of a path integration-based neural map. Herewe review how place cells and grid cells may form the basis for quantitativespatiotemporal representation of places, routes, and associated experiencesduring behavior and in memory. Because these cell types have some of the mostconspicuous behavioral correlates among neurons in nonsensory cortical systems,and because their spatial firing structure reflects computations internally inthe system, studies of entorhinal-hippocampal representations may offerconsiderable insight into general Principals of cortical network dynamics.

全文链接：http://www.annualreviews.org/doi/pdf/10.1146/annurev.neuro.31.061307.090723