Peng Jie, Long Ben, Yuan Jing, Peng Xue, Ni Hong, Li Xiangning, Gong Hui, Luo Qingming, Li Anan
Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and TechnologyWuhan, China.
Britton Chance Center, School of Engineering Sciences, Huazhong University of Science and TechnologyWuhan, China.
Front Neuroanat. 2017 Jul 25;11:63. doi: 10.3389/fnana.2017.00063. eCollection 2017.
Corticotropin-releasing hormone (CRH), with widespread expression in the brain, plays a key role in modulating a series of behaviors, including anxiety, arousal, motor function, learning and memory. Previous studies have focused on some brain regions with densely distributed CRH neurons such as paraventricular hypothalamic nucleus (PVH) and bed nuclei of the stria terminalis (BST) and revealed some basic structural and functional knowledge of CRH neurons. However, there is no systematic analysis of brain-wide distribution of CRH neurons. Here, we performed a comprehensive study of CRH neurons in mice via automatic imaging and stereoscopic cell counting in a whole mouse brain. We acquired four datasets of the CRH distributions with co-localized cytoarchitecture at a voxel resolution of 0.32 μm × 0.32 μm × 2 μm using brain-wide positioning system (BPS). Next, we precisely located and counted the EYFP-labeled neurons in different regions according to propidium iodide counterstained anatomical reference using Neuronal Global Position System. In particular, dense EYFP expression was found in piriform area, BST, central amygdalar nucleus, PVH, Barrington's nucleus, and inferior olivary complex. Considerable CRH neurons were also found in main olfactory bulb, medial preoptic nucleus, pontine gray, tegmental reticular nucleus, external cuneate nucleus, and midline thalamus. We reconstructed and compared the soma morphology of CRH neurons in 11 brain regions. The results demonstrated that CRH neurons had regional diversities of both cell distribution and soma morphology. This anatomical knowledge enhances the current understanding of the functions of CRH neurons. These results also demonstrated the ability of our platform to accurately orient, reconstruct and count neuronal somas in three-dimension for type-specific neurons in the whole brain, making it feasible to answer the fundamental neuroscience question of exact numbers of various neurons in the whole brain.
促肾上腺皮质激素释放激素（CRH）在大脑中广泛表达，在调节一系列行为中起关键作用，包括焦虑、觉醒、运动功能、学习和记忆。先前的研究集中在一些CRH神经元密集分布的脑区，如下丘脑室旁核（PVH）和终纹床核（BST），并揭示了CRH神经元的一些基本结构和功能知识。然而，目前尚无对CRH神经元全脑分布的系统分析。在此，我们通过对整个小鼠脑进行自动成像和立体细胞计数，对小鼠的CRH神经元进行了全面研究。我们使用全脑定位系统（BPS），以0.32μm×0.32μm×2μm的体素分辨率获取了四个具有共定位细胞结构的CRH分布数据集。接下来，我们根据碘化丙啶复染的解剖学参考，使用神经元全球定位系统在不同区域精确地定位和计数EYFP标记的神经元。特别地，在梨状区、BST、中央杏仁核、PVH、巴林顿核和下橄榄复合体中发现了密集的EYFP表达。在主嗅球、内侧视前核、脑桥灰质、被盖网状核、外侧楔核和中线丘脑也发现了相当数量的CRH神经元。我们重建并比较了11个脑区中CRH神经元的胞体形态。结果表明，CRH神经元在细胞分布和胞体形态上都具有区域多样性。这一解剖学知识增强了我们目前对CRH神经元功能的理解。这些结果还证明了我们的平台能够对全脑中特定类型的神经元进行三维精确的定向、重建和计数，从而使得回答全脑中各种神经元的确切数量这一基础神经科学问题成为可能。
