Data from: Mapping and analysis of the connectome of sympathetic premotor neurons in the rostral ventrolateral medulla of the rat using a volumetric brain atlas

Spinally projecting neurons in the rostral ventrolateral medulla (RVLM) play a critical role in the generation of vasomotor sympathetic tone and are thought to receive convergent input from neurons at every level of the neuraxis; the factors that determine their ongoing activity remain unresolved. In this study we use a genetically restricted viral tracing strategy to definitively map their spatially diffuse connectome.
We infected bulbospinal RVLM neurons with recombinant rabies variant that drives reporter expression in monosynaptically connected input neurons and mapped their distribution using a MRI-based volumetric atlas and a novel image alignment and visualization tool that efficiently translates the positions of neurons captured in conventional photomicrographs to Cartesian coordinates.
We identified prominent inputs from well-established neurohumoral and viscero-sympathetic sensory actuators, medullary autonomic and respiratory subnuclei, and supramedullary autonomic nuclei. The majority of inputs lay within the brainstem (88 – 94%), and included putative respiratory neurons in the pre-Bötzinger Complex and post-inspiratory complex that are therefore likely to underlie respiratory-sympathetic coupling. We also discovered a substantial and previously unrecognized input from the region immediately ventral to nucleus prepositus hypoglossi. In contrast, RVLM sympathetic premotor neurons were only sparsely innervated by suprapontine structures including the paraventricular nucleus, lateral hypothalamus, periaqueductal grey and superior colliculus, and we found almost no evidence of direct inputs from the cortex or amygdala.
Our approach can be used to quantify, standardize and share complete neuroanatomical datasets, and therefore provides researchers with a platform for presentation, analysis and independent analysis of connectomic data.

Usage Notes
Waxholm Rat Calculation TemplateThis template will help you to translate pixel co-ordinates of cells identified from microscopy images to Waxholm co-ordinates. In needs to be used in conjunction with the AlignNii image anchoring tool, which aligns 2d histological images in the 3d MRI Waxholm rat brain. Access to this tool can be requested from Jan Bjaalie ([e-mail]).Waxholm volumetric atlasThis is the zipped Imaris file that contains the Waxholm MRI dataset, the corresponding segmented dataset, the volumetric segmentation model and all of connectomic data from this paper.Dempsey 2016 RVLM Connectome Resource.zip

脊束旁腹侧核（RVLM）中的投射神经元在产生血管运动性交感神经紧张方面发挥着至关重要的作用，并被认为接收来自神经轴各层神经元的汇聚性输入；决定其持续活动的因素尚未得到解决。在本研究中，我们采用基因限制性病毒追踪策略，以明确绘制其空间扩散性连接组。我们感染了球状脊髓RVLM神经元，使用重组狂犬病变种病毒驱动单突触连接的输入神经元表达报告基因，并通过基于MRI的体积图谱和一种新颖的图像对齐及可视化工具，将这些神经元的分布位置从传统的显微照片坐标转换为笛卡尔坐标进行绘制。我们识别了来自已确立的神经体液和内脏交感神经感觉激活器、脑干自主神经和呼吸亚核，以及上位脑干自主神经核的显著输入。大多数输入位于脑干（88% - 94%），包括前Bötzinger复合体和吸气后复合体中的假设性呼吸神经元，因此它们可能是呼吸-交感耦合的基础。我们还发现了来自位于舌下神经核下方区域的一个巨大且先前未被认识到的输入。相比之下，RVLM交感前运动神经元仅由上位桥脑结构，包括室旁核、外侧下丘脑、导水管周围灰质和上丘，进行稀疏的神经支配，并且我们没有发现来自皮层或杏仁核的直接输入。我们的方法可用于量化、标准化和共享完整的神经解剖学数据集，因此为研究人员提供了一个展示、分析和独立分析连接组数据的平台。使用说明：Waxholm鼠计算模板此模板有助于将显微镜图像中识别的细胞像素坐标转换为Waxholm坐标。它需要与AlignNii图像锚定工具结合使用，该工具将2D组织学图像与3D Waxholm鼠脑MRI对齐。从Jan Bjaalie（[e-mail]）处请求访问此工具。Waxholm体积图谱这是包含Waxholm MRI数据集、相应的分割数据集、体积分割模型以及本文中的所有连接组数据的Imaris文件压缩包。Dempsey 2016 RVLM连接组资源.zip