Bernstein Center for Computational Neuroscience, Humboldt University, Berlin 10115, Germany.
Neuron. 2011 Apr 14;70(1):109-20. doi: 10.1016/j.neuron.2011.03.006.
For each environment a rodent has explored, its hippocampus contains a map consisting of a unique subset of neurons, called place cells, that have spatially tuned spiking there, with the remaining neurons being essentially silent. Using whole-cell recording in freely moving rats exploring a novel maze, we observed differences in intrinsic cellular properties and input-based subthreshold membrane potential levels underlying this division into place and silent cells. Compared to silent cells, place cells had lower spike thresholds and peaked versus flat subthreshold membrane potentials as a function of animal location. Both differences were evident from the beginning of exploration. Additionally, future place cells exhibited higher burst propensity before exploration. Thus, internal settings appear to predetermine which cells will represent the next novel environment encountered. Furthermore, place cells fired spatially tuned bursts with large, putatively calcium-mediated depolarizations that could trigger plasticity and stabilize the new map for long-term storage. Our results provide new insight into hippocampal memory formation.
对于啮齿动物探索过的每一个环境，其海马体中都包含一个由称为位置细胞的神经元的独特子集组成的地图，这些神经元在那里具有空间调谐的尖峰，而其余神经元基本上处于沉默状态。在自由移动的大鼠中使用全细胞记录来探索一个新的迷宫，我们观察到了这种位置细胞和沉默细胞的内在细胞特性和基于输入的亚阈膜电位水平的差异。与沉默细胞相比，位置细胞的尖峰阈值更低，并且亚阈膜电位随动物位置呈峰值而非平坦分布。这两个差异从探索开始就很明显。此外，未来的位置细胞在探索之前表现出更高的爆发倾向。因此，内部设置似乎预先决定了哪些细胞将代表下一个遇到的新环境。此外，位置细胞以大的、可能与钙有关的去极化形式发射空间调谐的爆发，这些爆发可以触发可塑性并稳定新的地图以供长期存储。我们的研究结果为海马体记忆形成提供了新的见解。
