ANATOMICAL AND ELECTROPHYSIOLOGICAL CHARACTERIZATION OF A POPULATION OF DI6 INTERNEURONS IN THE NEONATAL MOUSE SPINAL CORD
ANATOMICAL AND ELECTROPHYSIOLOGICAL CHARACTERIZATION OF A POPULATION OF DI6 INTERNEURONS IN THE NEONATAL MOUSE SPINAL CORD
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DOI：
10.1016/j.neuroscience.2017.08.031
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发表时间：
2017-10-24
期刊：
影响因子：
3.3
通讯作者：
Gosgnach, Simon
中科院分区：
文献类型：
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作者：
Griener, Anna;Zhang, Wei;Gosgnach, Simon
运动中枢模式发生器是位于尾脊髓腹侧的神经网络，是哺乳动物迈步的基础。虽然许多被认为构成该神经网络的基因定义的中间神经元已被识别和表征，但表达转录因子 WTI 和/或 DMRT3 的 dI6 细胞是定居在该区域的一个群体，在运动过程中很活跃，但对其功能知之甚少。这些细胞最初被假设为连合前运动中间神经元，但支持这一点的证据很少。在这里，我们使用 TgDbx1(cre);R26(EFP); 来表征该细胞群。 Dbx1(Lacz) 转基因小鼠系，已被证明是 dI6 中间神经元的有效标记。我们发现 dI6 细胞在整个脊髓的 VII 层和 VIII 层中丰富，并提供了表达 dI6 细胞的 WT1/DMRT3 之外的亚型可能存在的证据。逆行追踪实验表明，大多数 dI6 细胞投射下降轴突，有些细胞与脊髓两侧的运动神经元进行单突触或双突触接触。对它们在非重置缺失期间（发生在虚构运动期间）的活动进行分析表明，这些细胞参与运动节律的产生和模式形成。这项研究对 TgDbx1(cre);R26(EFP);Dbx1(Lacz) 转基因小鼠中标记的 dI6 细胞进行了全面的表征，并支持了先前的工作，表明这些细胞在运动活动中发挥多种作用。 (C) 2017 年国际广播组织。由爱思唯尔有限公司出版。保留所有权利。
The locomotor central pattern generator is a neural network located in the ventral aspect of the caudal spinal cord that underlies stepping in mammals. While many genetically defined interneurons that are thought to comprise this neural network have been identified and characterized, the dI6 cells- which express the transcription factors WTI and/or DMRT3- are one population that settle in this region, are active during locomotion, whose function is poorly understood. These cells were originally hypothesized to be commissural premotor interneurons, however evidence in support of this is sparse. Here we characterize this population of cells using the TgDbx1(cre);R26(EFP); Dbx1(Lacz) transgenic mouse line, which has been shown to be an effective marker of dI6 interneurons. We show dI6 cells to be abundant in laminae VII and VIII along the entire spinal cord and provide evidence that subtypes outside the WT1/DMRT3 expressing dI6 cells may exist. Retrograde tracing experiments indicate that the majority of dI6 cells project descending axons, and some make monosynaptic or disynaptic contacts onto motoneurons on either side of the spinal cord. Analysis of their activity during non-resetting deletions, which occur during bouts of fictive locomotion, suggests that these cells are involved in both locomotor rhythm generation and pattern formation. This study provides a thorough characterization of the dI6 cells labeled in the TgDbx1(cre);R26(EFP);Dbx1(Lacz) transgenic mouse, and supports previous work suggesting that these cells play multiple roles during locomotor activity. (C) 2017 IBRO. Published by Elsevier Ltd. All rights reserved.