Liang Huazheng, Watson Charles, Paxinos George
Neuroscience Research Australia, Barker Street, Randwick, NSW, 2031, Australia.
School of Medical Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
Brain Struct Funct. 2016 Apr;221(3):1623-33. doi: 10.1007/s00429-015-0993-z. Epub 2015 Jan 30.
The present study investigated the projections of the gigantocellular reticular nucleus (Gi) and its neighbors--the dorsal paragigantocellular reticular nucleus (DPGi), the alpha/ventral part of the gigantocellular reticular nucleus (GiA/V), and the lateral paragigantocellular reticular nucleus (LPGi)--to the mouse spinal cord by injecting the anterograde tracer biotinylated dextran amine (BDA) into the Gi, DPGi, GiA/GiV, and LPGi. The Gi projected to the entire spinal cord bilaterally with an ipsilateral predominance. Its fibers traveled in both the ventral and lateral funiculi with a greater presence in the ventral funiculus. As the fibers descended in the spinal cord, their density in the lateral funiculus increased. The terminals were present mainly in laminae 7-10 with a dorsolateral expansion caudally. In the lumbar and sacral cord, a considerable number of terminals were also present in laminae 5 and 6. Contralateral fibers shared a similar pattern to their ipsilateral counterparts and some fibers were seen to cross the midline. Fibers arising from the DPGi were similarly distributed in the spinal cord except that there was no dorsolateral expansion in the lumbar and sacral segments and there were fewer fiber terminals. Fibers arising from GiA/V predominantly traveled in the ventral and lateral funiculi ipsilaterally. Ipsilaterally, the density of fibers in the ventral funiculus decreased along the rostrocaudal axis, whereas the density of fibers in the lateral funiculus increased. They terminate mainly in the medial ventral horn and lamina 10 with a smaller number of fibers in the dorsal horn. Fibers arising from the LPGi traveled in both the ventral and lateral funiculi and the density of these fibers in the ventral and lateral funiculi decreased dramatically in the lumbar and sacral segments. Their terminals were present in the ventral horn with a large portion of them terminating in the motor neuron columns. The present study is the first demonstration of the termination pattern of fibers arising from the Gi, DPGi, GiA/GiV, and LPGi in the mouse spinal cord. It provides an anatomical foundation for those who are conducting spinal cord injury and locomotion related research.
本研究通过将顺行示踪剂生物素化葡聚糖胺（BDA）注射到巨细胞网状核（Gi）、背侧旁巨细胞网状核（DPGi）、巨细胞网状核α/腹侧部（GiA/V）和外侧旁巨细胞网状核（LPGi）中，研究了这些核团及其邻近区域向小鼠脊髓的投射。Gi双侧投射至整个脊髓，以同侧为主。其纤维在腹侧和外侧索中走行，在腹侧索中更为密集。随着纤维在脊髓中下行，它们在外侧索中的密度增加。终末主要位于第7 - 10层，在尾侧有背外侧扩展。在腰段和骶段脊髓，第5和6层也有相当数量的终末。对侧纤维与其同侧对应纤维分布模式相似，且一些纤维可穿过中线。来自DPGi的纤维在脊髓中的分布类似，但在腰段和骶段没有背外侧扩展，纤维终末较少。来自GiA/V的纤维主要在同侧的腹侧和外侧索中走行。在同侧，腹侧索中纤维的密度沿头尾轴下降，而外侧索中纤维的密度增加。它们主要终末于内侧腹角和第10层，背角中的纤维较少。来自LPGi的纤维在腹侧和外侧索中走行，在腰段和骶段，这些纤维在腹侧和外侧索中的密度显著降低。它们的终末位于腹角，其中大部分终末于运动神经元柱。本研究首次展示了来自Gi、DPGi、GiA/GiV和LPGi的纤维在小鼠脊髓中的终末模式。它为从事脊髓损伤和运动相关研究的人员提供了解剖学基础。
