A mathematical model of negative covariability of inter-columnar excitatory synaptic actions caused by presynaptic inhibition
A mathematical model of negative covariability of inter-columnar excitatory synaptic actions caused by presynaptic inhibition
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突触前抑制引起的柱间兴奋性突触动作负协变性的数学模型
DOI：
10.1111/ejn.12299
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Kang Y
中科院分区：
文献类型：
--
作者：
Saito M;Tanaka T;Sato H;Toyoda H;Aoyagi T;Kang Y
我们之前已经表明，位于相互相邻列中的两层第三锥体细胞（PC）的皮质内兴奋性突触作用之间的正协变性通过皮质内输入的逐列突触前抑制而变成负协变性，这暗示着皮质内兴奋性突触作用之间的正协变性。柱间突触作用去同步的基础。在这里，我们通过使用数学模型研究了突触前抑制的强度或其他因素如何调节柱间去突触化。基于我们先前关于位于刺激的归属柱（HC）中的PC中诱发的皮质内兴奋性突触后电流（EPSC）的成对脉冲抑制（PPD）而位于相邻柱（AC）中的PC中没有PPD的发现，构建了PC与抑制性中间神经元之间突触连接的数学模型。当配对脉冲比（PPR）降低到0.80以上时，位于HC和AC的配对PC中的两个第二EPSC幅度之间的相关系数与位于同一HC的配对PC中的两个第二EPSC幅度之间的相关系数呈现相反的变化，并且在几乎相同的PPR（0.40）处分别达到全局负最大值和局部正最大值。在该PPR处，将最大化相互相邻列中的两个电池组件之间的去极化。这些积极的和消极的协变没有产生背景振荡同步跨列，并通过增加同步幅度增强，表明同步导致的去同步化。我们认为，从柱状突触前抑制中解放出来后，可能会出现一种缓慢的振荡同步。
We previously showed that a positive covariability between intracortical excitatory synaptic actions onto the two layer three pyramidal cells (PCs) located in mutually adjacent columns is changed into a negative covariability by column‐wise presynaptic inhibition of intracortical inputs, implicated as a basis for the desynchronization of inter‐columnar synaptic actions. Here we investigated how the inter‐columnar desynchronization is modulated by the strength of presynaptic inhibition or other factors, by using a mathematical model. Based on our previous findings on the paired‐pulse depression (PPD) of intracortical excitatory postsynaptic currents (EPSCs) evoked in PCs located in the stimulated home column (HC) but no PPD in PCs located in the adjacent column (AC), a mathematical model of synaptic connections between PCs and inhibitory interneurons was constructed. When the paired‐pulse ratio (PPR) was decreased beyond 0.80, the correlation coefficient between the two second EPSC amplitudes in the paired PCs located in the HC and AC and that in the paired PCs located in the same HC exhibited opposite changes, and reached a global negative maximum and local positive maximum, respectively, at almost the same PPR (0.40). At this PPR, the desynchronization between the two cell assemblies in mutually adjacent columns would be maximized. These positive and negative covariabilities were not produced without background oscillatory synchronization across columns and were enhanced by increasing the synchronization magnitude, indicating that the synchronization leads to the desynchronization. We propose that a slow oscillatory synchronization across columns may emerge following the liberation from the column‐wise presynaptic inhibition of inter‐columnar synaptic inputs.