Raastad M, Lipowski R
Department of Neurophysiology, University of Oslo, Norway.
Eur J Neurosci. 1996 Jun;8(6):1265-74. doi: 10.1111/j.1460-9568.1996.tb01295.x.
Different CA3 cells may have dissimilar effects on a CA1 pyramidal cell. In order to test this idea, we studied the amplitude distribution of excitatory postsynaptic currents (EPSCs) in response to weak electrical stimulation of presynaptic axons in the rat hippocampal slice. We accepted the response populations as representative for the effect of, in most cases, a single axon when the EPSCs appeared at a certain threshold stimulation strength, with the subsequent lack of increase in amplitude with further stimulation increase. By comparing the EPSC amplitude distributions obtained from different synaptic inputs to the same CA1 cell, we found differences in the failure probability and the EPSC amplitude, each of which contributed to differences in the mean response amplitude. We conclude that not only the number but also the specific subset of active CA3 cells is important for the synaptically driven discharge of a given CA1 cell.
不同的CA3细胞可能对CA1锥体细胞产生不同的影响。为了验证这一观点，我们研究了大鼠海马切片中，对突触前轴突进行弱电刺激时，兴奋性突触后电流（EPSC）的幅度分布。当EPSC在一定阈值刺激强度下出现，且随着刺激强度进一步增加幅度不再增大时，我们将这种反应群体视为在大多数情况下单个轴突作用的代表。通过比较来自同一CA1细胞不同突触输入的EPSC幅度分布，我们发现失败概率和EPSC幅度存在差异，每一个差异都导致了平均反应幅度的不同。我们得出结论，对于给定CA1细胞的突触驱动放电而言，不仅活跃的CA3细胞数量，而且其特定子集都很重要。
