Estimating functional connectivity in an electrically coupled interneuron network
Estimating functional connectivity in an electrically coupled interneuron network
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DOI：
10.1073/pnas.1310983110
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发表时间：
2013-12-03
影响因子：
11.1
通讯作者：
Marty, Alain
中科院分区：
文献类型：
--
作者：
Alcami, Pepe;Marty, Alain
尽管人们早就知道在许多哺乳动物大脑区域中神经元是电耦合的，但仍然缺乏对网络电连接及其对细胞被动特性影响的定量描述。迄今为止用于解决该问题的方法是有限的，因为它们不容易区分直接相邻单元之间的连接和涉及中间多重连接单元的间接连接。在小脑皮质中，解剖学和功能证据表明分子层中间神经元（篮状细胞和星状细胞）之间存在电耦合。对幼年大鼠或小鼠分子层中间神经元电压钳下获得的电容电流的分析揭示了时间常数类似于 20 ms 的指数分量，这代表通过间隙连接的相邻细胞的电容负载。这些结果与电突触的双细胞记录相结合，使我们估计大鼠篮状细胞的直接邻居数量约为 4，大鼠星状细胞的直接邻居数量约为 1。篮状电池中的加权邻居数（直接和间接的邻居数，以稳态电压偏转百分比加权）为 1.69，星状电池为 0.23。最后的数字表明网络中潜在变化的传播，并用于估计间隙连接对细胞输入电导的贡献。总之，本工作提供了有效的工具来分析电连接的中间神经元网络的连接性，并且表明在幼年啮齿动物中，篮状细胞之间的电通讯比星状细胞之间的电通讯更强。
Even though it has been known for some time that in many mammalian brain areas interneurons are electrically coupled, a quantitative description of the network electrical connectivity and its impact on cellular passive properties is still lacking. Approaches used so far to solve this problem are limited because they do not readily distinguish junctions among direct neighbors from indirect junctions involving intermediary, multiply connected cells. In the cerebellar cortex, anatomical and functional evidence indicates electrical coupling between molecular layer interneurons (basket and stellate cells). An analysis of the capacitive currents obtained under voltage clamp in molecular layer interneurons of juvenile rats or mice reveals an exponential component with a time constant of similar to 20 ms, which represents capacitive loading of neighboring cells through gap junctions. These results, taken together with dual cell recording of electrical synapses, have led us to estimate the number of direct neighbors to be similar to 4 for rat basket cells and similar to 1 for rat stellate cells. The weighted number of neighbors (number of neighbors, both direct and indirect, weighted with the percentage of voltage deflection at steady state) was 1.69 in basket cells and 0.23 in stellate cells. The last numbers indicate the spread of potential changes in the network and serve to estimate the contribution of gap junctions to cellular input conductance. In conclusion the present work offers effective tools to analyze the connectivity of electrically connected interneuron networks, and it indicates that in juvenile rodents, electrical communication is stronger among basket cells than among stellate cells.