Human Brain Research Laboratory, Institute of Experimental Medicine, ELKH, Budapest, Hungary.
Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary.
Brain Struct Funct. 2021 Jan;226(1):281-296. doi: 10.1007/s00429-020-02182-8. Epub 2020 Dec 23.
Betz cells-the gigantopyramidal neurons found in high amount in the primary motor cortex-are among of the most characteristic neuronal cells. A part of them contains the calcium-binding protein parvalbumin (PV) in primates. However, less is known about these cells in the human motor cortex despite their important role in different neurological disorders. Therefore, the aim of our study was to investigate the neurochemical features and perisomatic input properties of Betz cells in control human samples with short post-mortem interval. We used different microscopic techniques to investigate the primary motor cortex of both hemispheres. The soma size and density, and expression of PV of the Betz cells were investigated. Furthermore, we used confocal fluorescent and electron microscopy to examine their perisomatic input. The soma size and density showed moderate variability among samples and hemispheres. Post-mortem interval and hemispherical localization did not influence these features. Around 70% of Betz cells expressed PV, but in less intensity than the cortical interneurons. Betz neurons receive dense perisomatic input, which are mostly VIAAT- (vesicular inhibitory amino acid transporter) and PV immunopositive. In the electron microscope, we found PV-immunolabelled terminals with asymmetric-like synaptic structure, too. Terminals with morphologically similar synaptic specialisation were also found among vGluT2- (vesicular glutamate transporter type 2) immunostained terminals contacting Betz cells. Our data suggest that Betz cells' morphological properties showed less variability among subjects and hemispheres than the density of them. Their neurochemical and perisomatic input characteristics support their role in execution of fast and precise movements.
贝茨细胞——在初级运动皮层中大量存在的巨大金字塔形神经元——是最具特征性的神经元细胞之一。其中一部分在灵长类动物中含有钙结合蛋白 parvalbumin（PV）。然而，尽管它们在不同的神经紊乱中起着重要作用，但在人类运动皮层中，这些细胞的了解较少。因此，我们的研究目的是在尸检间隔时间较短的对照人体样本中研究贝茨细胞的神经化学特征和体周输入特性。我们使用不同的显微镜技术来研究两个半球的初级运动皮层。研究了贝茨细胞的体大小和密度以及 PV 的表达。此外，我们使用共聚焦荧光和电子显微镜检查它们的体周输入。体大小和密度在样本和半球之间表现出中等的可变性。尸检间隔时间和半球定位没有影响这些特征。大约 70%的贝茨细胞表达 PV，但强度低于皮质中间神经元。贝茨神经元接收密集的体周输入，主要是 VIAAT-（囊泡抑制性氨基酸转运体）和 PV 免疫阳性。在电子显微镜下，我们还发现了具有不对称样突触结构的 PV 免疫标记末端。在与贝茨细胞接触的 vGluT2-（囊泡谷氨酸转运体 2）免疫染色末端中，也发现了具有形态相似突触特化的末端。我们的数据表明，贝茨细胞的形态特征在个体和半球之间的变异性小于它们的密度。它们的神经化学和体周输入特征支持它们在执行快速和精确运动中的作用。
