Multiquantal release underlies the distribution of synaptic efficacies in the neocortex
Multiquantal release underlies the distribution of synaptic efficacies in the neocortex
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DOI：
10.3389/neuro.10.027.2009
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发表时间：
2009-11-01
影响因子：
3.2
通讯作者：
Richardson, Magnus J. E.
中科院分区：
文献类型：
--
作者：
Loebel, Alex;Silberberg, Gilad;Richardson, Magnus J. E.
锥体间突触连接的特征在于大范围的EPSP振幅。虽然在不同的大脑区域和跨层反复观察，但对促成这一广泛范围的突触特征知之甚少。特别地，该范围可能由突触传递的量子模型的所有三个参数的差异来解释，即释放位点的数量、释放概率和量子大小。在这里，我们提出了一个严格的统计分析的兴奋性突触连接层5锥体神经元的躯体感觉皮层之间的传输特性。我们的中心发现是，EPSP振幅与估计的释放位点的数量密切相关，但与释放概率或量子大小无关。此外，我们发现，释放位点的数量可以比这种类型的连接的突触接触的典型数量高出一个数量级以上。我们的研究结果表明，在较强的突触连接的传输介导的多量子释放从他们的突触接触。我们认为，调节释放位点的数量可能是调节新皮层突触传递的一个重要机制。
Inter-pyramidal synaptic connections are characterized by a wide range of EPSP amplitudes. Although repeatedly observed at different brain regions and across layers, little is known about the synaptic characteristics that contribute to this wide range. In particular, the range could potentially be accounted for by differences in all three parameters of the quantal model of synaptic transmission, i.e. the number of release sites, release probability and quantal size. Here, we present a rigorous statistical analysis of the transmission properties of excitatory synaptic connections between layer-5 pyramidal neurons of the somato-sensory cortex. Our central finding is that the EPSP amplitude is strongly correlated with the number of estimated release sites, but not with the release probability or quantal size. In addition, we found that the number of release sites can be more than an order of magnitude higher than the typical number of synaptic contacts for this type of connection. Our findings indicate that transmission at stronger synaptic connections is mediated by multiquantal release from their synaptic contacts. We propose that modulating the number of release sites could be an important mechanism in regulating neocortical synaptic transmission.