Wolfson Institute for Biomedical Research, University College London, London, UK.
Nat Neurosci. 2013 Mar;16(3):325-31. doi: 10.1038/nn.3340. Epub 2013 Feb 10.
Neurons in the medial entorhinal cortex exhibit a grid-like spatial pattern of spike rates that has been proposed to represent a neural code for path integration. To understand how grid cell firing arises from the combination of intrinsic conductances and synaptic input in medial entorhinal stellate cells, we performed patch-clamp recordings in mice navigating in a virtual-reality environment. We found that the membrane potential signature of stellate cells during firing field crossings consisted of a slow depolarization driving spike output. This was best predicted by network models in which neurons receive sustained depolarizing synaptic input during a field crossing, such as continuous attractor network models of grid cell firing. Another key feature of the data, phase precession of intracellular theta oscillations and spiking with respect to extracellular theta oscillations, was best captured by an oscillatory interference model. Thus, these findings provide crucial new information for a quantitative understanding of the cellular basis of spatial navigation in the entorhinal cortex.
内侧缰状回皮层中的神经元表现出一种网格状的尖峰发放率空间模式，这种模式被提出用于表示路径整合的神经编码。为了了解网格细胞放电如何源自内侧缰状回星形细胞的内在电导和突触输入的组合，我们在导航于虚拟现实环境中的小鼠中进行了膜片钳记录。我们发现，在放电场穿越期间，星形细胞的膜电位特征由驱动尖峰输出的缓慢去极化组成。这是由网络模型最好地预测的，在这些模型中，神经元在穿越场时接收持续的去极化突触输入，例如网格细胞放电的连续吸引子网络模型。数据的另一个关键特征，即细胞内θ振荡的相位超前和相对于细胞外θ振荡的尖峰发放，由振荡干扰模型最好地捕捉。因此，这些发现为定量理解内侧缰状回皮层中空间导航的细胞基础提供了至关重要的新信息。
