Baizer Joan S, Witelson Sandra F
Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.
Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.
Front Neuroanat. 2023 Feb 16;17:1069210. doi: 10.3389/fnana.2023.1069210. eCollection 2023.
It is commonly thought that while the organization of the cerebral cortex changes dramatically over evolution, the organization of the brainstem is conserved across species. It is further assumed that, as in other species, brainstem organization is similar from one human to the next. We will review our data on four human brainstem nuclei that suggest that both ideas may need modification.
We have studied the neuroanatomical and neurochemical organization of the nucleus paramedianus dorsalis (PMD), the principal nucleus of the inferior olive (IOpr), the arcuate nucleus of the medulla (Arc) and the dorsal cochlear nucleus (DC). We compared these human brainstem nuclei to nuclei in other mammals including chimpanzees, monkeys, cats and rodents. We studied human cases from the Witelson Normal Brain collection using Nissl and immunostained sections, and examined archival Nissl and immunostained sections from other species.
We found significant individual variability in the size and shape of brainstem structures among humans. There is left-right asymmetry in the size and appearance of nuclei, dramatically so in the IOpr and Arc. In humans there are nuclei, e.g., the PMD and the Arc, not seen in several other species. In addition, there are brainstem structures that are conserved across species but show major expansion in humans, e.g., the IOpr. Finally, there are nuclei, e.g. the DC, that show major differences in structure among species.
Overall, the results suggest several principles of human brainstem organization that distinguish humans from other species. Studying the functional correlates of, and the genetic contributions to, these brainstem characteristics are important future research directions.
人们普遍认为，虽然大脑皮层的组织在进化过程中发生了巨大变化，但脑干的组织在物种间是保守的。人们还进一步假定，与其他物种一样，人类个体之间的脑干组织相似。我们将回顾我们关于四个人类脑干核的数据，这些数据表明这两种观点可能都需要修正。
我们研究了背侧旁正中核（PMD）、下橄榄主核（IOpr）、延髓弓状核（Arc）和蜗背侧核（DC）的神经解剖学和神经化学组织。我们将这些人类脑干核与其他哺乳动物（包括黑猩猩、猴子、猫和啮齿动物）的核进行了比较。我们使用尼氏染色和免疫染色切片研究了来自威特森正常脑库的人类病例，并检查了来自其他物种的存档尼氏染色和免疫染色切片。
我们发现人类脑干结构的大小和形状存在显著的个体差异。核的大小和外观存在左右不对称，在IOpr和Arc中尤为明显。在人类中存在一些在其他几个物种中未见到的核，例如PMD和Arc。此外，有一些脑干结构在物种间是保守的，但在人类中显示出主要的扩张，例如IOpr。最后，有一些核，例如DC，在物种间显示出结构上的主要差异。
总体而言，结果表明了人类脑干组织的几个原则，这些原则将人类与其他物种区分开来。研究这些脑干特征的功能相关性和遗传贡献是未来重要的研究方向。
