Center for Neural Informatics, Structures, and Plasticity, Interdisciplinary Neuroscience Program, Krasnow Institute for Advanced Study, Fairfax, Virginia, USA.
Bioengineering Department and Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA.
Eur J Neurosci. 2022 Apr;55(7):1724-1741. doi: 10.1111/ejn.15639. Epub 2022 Mar 27.
Quantifying the population sizes of distinct neuron types in different anatomical regions is an essential step towards establishing a brain cell census. Although estimates exist for the total neuronal populations in different species, the number and definition of each specific neuron type are still intensively investigated. Hippocampome.org is an open-source knowledge base with morphological, physiological and molecular information for 122 neuron types in the rodent hippocampal formation. While such framework identifies all known neuron types in this system, their relative abundances remain largely unknown. This work quantitatively estimates the counts of all Hippocampome.org neuron types by literature mining and numerical optimization. We report the number of neurons in each type identified by main neurotransmitter (glutamate or GABA) and axonal-dendritic patterns throughout 26 subregions and layers of the dentate gyrus, Ammon's horn, subiculum and entorhinal cortex. We produce by sensitivity analysis reliable numerical ranges for each type and summarize the amounts across broad neuronal families defined by biomarkers expression and firing dynamics. Study of density distributions indicates that the number of dendritic-targeting interneurons, but not of other neuronal classes, is independent of anatomical volumes. All extracted values, experimental evidence and related software code are released on Hippocampome.org.
量化不同解剖区域中不同神经元类型的群体大小是建立脑细胞普查的重要步骤。尽管对于不同物种的总神经元群体存在估计，但每个特定神经元类型的数量和定义仍在深入研究中。Hippocampome.org 是一个开源知识库，包含啮齿动物海马结构中 122 种神经元类型的形态、生理和分子信息。虽然该框架确定了该系统中所有已知的神经元类型，但它们的相对丰度仍然很大程度上未知。这项工作通过文献挖掘和数值优化定量估计了所有 Hippocampome.org 神经元类型的数量。我们报告了通过主要神经递质（谷氨酸或 GABA）和轴突-树突模式在齿状回、Ammon 角、下托和内嗅皮层的 26 个亚区和层中识别出的每种类型的神经元数量。我们通过敏感性分析为每种类型产生可靠的数值范围，并根据生物标志物表达和发射动力学定义的广泛神经元家族总结数量。密度分布的研究表明，靶向树突的中间神经元的数量，而不是其他神经元类别的数量，与解剖体积无关。所有提取的值、实验证据和相关软件代码都在 Hippocampome.org 上发布。
