Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, 410013, Hunan, China.
Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
Mol Neurobiol. 2023 Jun;60(6):3464-3485. doi: 10.1007/s12035-023-03261-7. Epub 2023 Mar 6.
A cohort of morphologically heterogenous doublecortin immunoreactive (DCX +) "immature neurons" has been identified in the cerebral cortex largely around layer II and the amygdala largely in the paralaminar nucleus (PLN) among various mammals. To gain a wide spatiotemporal view on these neurons in humans, we examined layer II and amygdalar DCX + neurons in the brains of infants to 100-year-old individuals. Layer II DCX + neurons occurred throughout the cerebrum in the infants/toddlers, mainly in the temporal lobe in the adolescents and adults, and only in the temporal cortex surrounding the amygdala in the elderly. Amygdalar DCX + neurons occurred in all age groups, localized primarily to the PLN, and reduced in number with age. The small-sized DCX + neurons were unipolar or bipolar, and formed migratory chains extending tangentially, obliquely, and inwardly in layers I-III in the cortex, and from the PLN to other nuclei in the amygdala. Morphologically mature-looking neurons had a relatively larger soma and weaker DCX reactivity. In contrast to the above, DCX + neurons in the hippocampal dentate gyrus were only detected in the infant cases in parallelly processed cerebral sections. The present study reveals a broader regional distribution of the cortical layer II DCX + neurons than previously documented in human cerebrum, especially during childhood and adolescence, while both layer II and amygdalar DCX + neurons persist in the temporal lobe lifelong. Layer II and amygdalar DCX + neurons may serve as an essential immature neuronal system to support functional network plasticity in human cerebrum in an age/region-dependent manner.
在各种哺乳动物的大脑皮层中，主要在 II 层周围和杏仁核中，发现了形态上异质的双皮质素免疫反应性 (DCX+)“未成熟神经元”群。为了更广泛地观察人类这些神经元，我们检查了婴儿至 100 岁个体大脑中的 II 层和杏仁核 DCX+神经元。在婴儿/幼儿中，II 层 DCX+神经元出现在大脑的各个区域，主要在青少年和成人的颞叶，而在老年人中仅出现在围绕杏仁核的颞叶皮层。杏仁核 DCX+神经元存在于所有年龄组，主要位于 PLN，并且随年龄而减少。小尺寸的 DCX+神经元为单极或双极，并且在皮层的 I-III 层中形成延伸的迁移链，以切线、倾斜和向内延伸，从 PLN 延伸到杏仁核的其他核。形态成熟的神经元具有相对较大的体和较弱的 DCX 反应性。与上述情况相反，仅在并行处理的大脑切片中在婴儿病例中检测到海马齿状回的 DCX+神经元。本研究揭示了人类大脑中皮层 II 层 DCX+神经元的区域分布比以前记录的更广泛，尤其是在儿童和青少年时期，而 II 层和杏仁核的 DCX+神经元在颞叶终生存在。II 层和杏仁核的 DCX+神经元可能作为一种必需的未成熟神经元系统，以依赖年龄/区域的方式支持人类大脑的功能网络可塑性。
