Stepanyants Armen, Tamás Gábor, Chklovskii Dmitri B
Cold Spring Harbor Laboratory, New York 11724, USA.
Neuron. 2004 Jul 22;43(2):251-9. doi: 10.1016/j.neuron.2004.06.013.
Brain function relies on specificity of synaptic connectivity patterns among different classes of neurons. Yet, the substrates of specificity in complex neuropil remain largely unknown. We search for imprints of specificity in the layout of axonal and dendritic arbors from the rat neocortex. An analysis of 3D reconstructions of pairs consisting of pyramidal cells (PCs) and GABAergic interneurons (GIs) revealed that the layout of GI axons is specific. This specificity is manifested in a relatively high tortuosity, small branch length of these axons, and correlations of their trajectories with the positions of postsynaptic neuron dendrites. Axons of PCs show no such specificity, usually taking a relatively straight course through neuropil. However, wiring patterns among PCs hold a large potential for circuit remodeling and specificity through growth and retraction of dendritic spines. Our results define distinct class-specific rules in establishing synaptic connectivity, which could be crucial in formulating a canonical cortical circuit.
脑功能依赖于不同类型神经元之间突触连接模式的特异性。然而，复杂神经纤维网中特异性的基础在很大程度上仍不清楚。我们在大鼠新皮质的轴突和树突分支布局中寻找特异性的印记。对由锥体细胞（PCs）和γ-氨基丁酸能中间神经元（GIs）组成的细胞对进行三维重建分析发现，GI轴突的布局具有特异性。这种特异性表现为这些轴突相对较高的曲折度、较短的分支长度，以及它们的轨迹与突触后神经元树突位置的相关性。PCs的轴突没有这种特异性，通常在神经纤维网中走相对笔直的路线。然而，PCs之间的布线模式通过树突棘的生长和回缩在电路重塑和特异性方面具有很大潜力。我们的结果定义了建立突触连接时不同的类别特异性规则，这对于构建典型的皮质回路可能至关重要。
