Stereotypical bouton clustering of individual neurons in cat primary visual cortex
Stereotypical bouton clustering of individual neurons in cat primary visual cortex
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DOI：
10.1523/jneurosci.3753-07.2007
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发表时间：
2007-11-07
影响因子：
5.3
通讯作者：
Martin, Kevan A. C.
中科院分区：
文献类型：
--
作者：
Binzegger, Tom;Douglas, Rodney J.;Martin, Kevan A. C.
在所有检查的物种中，除啮齿动物外，新皮质神经元的轴突在多个单独的簇中形成胸子。群集的大多数描述都是轶事，因此我们在这里开发了一种客观方法来识别簇。我们将平均迁移群集偏金属应用于39个单个神经元和来自CAT主要视觉皮层的三个丘脑传入的三维重建。刺（26中的20个）和光滑（13个中的7个）神经元至少形成了两个不同的椭圆形簇（范围为2-7）。对于所有细胞类型，簇的形成都是异质的，但受调节，因此簇的大小和分配给群集的胸子数量随着神经元形成的簇数的增加而均等。簇内的bouton密度与轴突的空间尺度成反比，使光滑神经元的密度高四倍。因此，光滑神经元的抑制作用比刺神经元的兴奋性作用要浓缩和局灶性得多。胸子数量最高的簇通常位于父神经元的躯体周围或之上。到下一个群集的距离与主要簇的直径成正比，这表明神经元的横向影响有最佳距离和空间焦点。因此，聚类轴突的横向传播可能支持将信号路由到局部位点的类似辐条的网络体系结构，从而降低了信号相关性和冗余。
In all species examined, with the exception of rodents, the axons of neocortical neurons form boutons in multiple separate clusters. Most descriptions of clusters are anecdotal, so here we developed an objective method for identifying clusters. We applied a mean-shift cluster-algorithm to three-dimensional reconstructions of 39 individual neurons and three thalamic afferents from the cat primary visual cortex. Both spiny (20 of 26) and smooth (7 of 13) neurons formed at least two distinct ellipsoidal clusters (range, 2-7). For all cell types, cluster formation is heterogenous, but is regulated so that cluster size and the number of boutons allocated to a cluster equalize with increasing number of clusters formed by a neuron. The bouton density within a cluster is inversely related to the spatial scale of the axon, resulting in a four times greater density for smooth neurons than for spiny neurons. Thus, the inhibitory action of the smooth neurons is much more concentrated and focal than the excitatory action of spiny neurons. The cluster with the highest number of boutons (primary cluster) was typically located around or above the soma of the parent neuron. The distance to the next cluster was proportional to the diameter of the primary cluster, suggesting that there is an optimal distance and spatial focus of the lateral influence of a neuron. The lateral spread of clustered axons may thus support a spoke-like network architecture that routes signals to localized sites, thereby reducing signal correlation and redundancy.