BackgroundMovement performance depends on the synaptic interactions generated by coherent parallel sensorimotor cortical outputs to different downstream targets. The major outputs of the neocortex to subcortical structures are driven by pyramidal tract neurons (PTNs) located in layer 5B. One of the main targets of PTNs is the spinal cord through the corticospinal (CS) system, which is formed by a complex collection of distinct CS circuits. However, little is known about intracortical synaptic interactions that originate CS commands and how different populations of CS neurons are functionally organized. To further understand the functional organization of the CS system, we analyzed the activity of unambiguously identified CS neurons projecting to different zones of the same spinal cord segment using two-photon calcium imaging and retrograde neuronal tracers.ResultsSensorimotor cortex slices obtained from transgenic mice expressing GCaMP6 funder the Thy1 promoter were used to analyze the spontaneous calcium transients in layer 5 pyramidal neurons. Distinct subgroups of CS neurons projecting to dorsal horn and ventral areas of the same segment show more synchronous activity between them than with other subgroups.ConclusionsThe results indicate that CS neurons projecting to different spinal cord zones segregated into functional ensembles depending on their hodology, suggesting that a modular organization of CS outputs controls sensorimotor behaviors in a coordinated manner.

中文翻译：

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小鼠皮质脊髓系统包含不同的功能性神经元集合，这取决于它们的 hodology

背景运动性能取决于对不同下游目标的连贯平行感觉运动皮层输出产生的突触相互作用。新皮层到皮层下结构的主要输出由位于第 5B 层的锥体束神经元 (PTN) 驱动。PTN 的主要目标之一是通过皮质脊髓 (CS) 系统的脊髓，该系统由不同 CS 回路的复杂集合形成。然而，对于产生 CS 命令的皮层内突触相互作用以及不同群体的 CS 神经元在功能上是如何组织的，我们知之甚少。为了进一步了解 CS 系统的功能组织，我们使用双光子钙成像和逆行神经元示踪剂分析了投射到同一脊髓节段不同区域的明确识别的 CS 神经元的活动。结果从表达 GCaMP6 的转基因小鼠获得的感觉运动皮层切片用于分析自发性钙第 5 层锥体神经元中的瞬变。投射到同一节段背角和腹侧区域的 CS 神经元的不同亚组比其他亚组表现出更多的同步活动。 CS 输出的模块化组织以协调的方式控制感觉运动行为。结果从表达 GCaMP6 的转基因小鼠获得的感觉运动皮层切片为 Thy1 启动子提供资金，用于分析第 5 层锥体神经元中的自发钙瞬变。投射到同一节段背角和腹侧区域的 CS 神经元的不同亚组比其他亚组表现出更多的同步活动。 CS 输出的模块化组织以协调的方式控制感觉运动行为。结果从表达 GCaMP6 的转基因小鼠获得的感觉运动皮层切片为 Thy1 启动子提供资金，用于分析第 5 层锥体神经元中的自发钙瞬变。投射到同一节段背角和腹侧区域的 CS 神经元的不同亚组比其他亚组表现出更多的同步活动。 CS 输出的模块化组织以协调的方式控制感觉运动行为。