虽然成年之后的海马中的神经发生在小鼠等动物中得到很好的确认,但是关于成年之后神经发生在灵长类的皮层和海马是否存在一直存在争议。半个世纪以来,不同的科学家使用不用的实验方法得出了不一样的结论。2018年3月7日,由UCSF的Arturo Alvaez Buylla实验室、复旦大学脑科学研究院杨振刚实验室和西班牙巴伦西亚大学 Jose Manuel Garcia-Verdugo实验室合作完成的Nature长文(Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults)表明人的海马在成年之后不会有神经发生,对灵长类中成年之后神经发生作为可塑性一种的理论提出了否定性证据。包括BioArt在内的许多媒体对此进行了详尽的报道。
然而,2018年4月5日的Cell Stem Cell发表了美国哥伦比亚大学Boldrini实验室的最新成果(Human Hippocampal Neurogenesis Persists throughout Aging),他们的结果表明神经发生不仅存在于成年人的海马,而且存在于老年人的海马,并且在数量上没有差异。
截然相反的结论一不小心就连发CNS,我们该相信哪一个的结果呢?作为吃瓜群众,真希望当我老了,神经发生还在继续。
Nature长文题目摘要:
New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus. This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease. In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day, whereas other studies find many fewer putative new neurons. Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal development. We also find that the number of proliferating progenitors and young neurons in the dentate gyrus declines sharply during the first year of life and only a few isolated young neurons are observed by 7 and 13 years of age. In adult patients with epilepsy and healthy adults (18-77 years; n = 17 post-mortem samples from controls; n = 12 surgical resection samples from patients with epilepsy), young neurons were not detected in the dentate gyrus. In the monkey (Macaca mulatta) hippocampus, proliferation of neurons in the subgranular zone was found in early postnatal life, but this diminished during juvenile development as neurogenesis decreased. We conclude that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans. The early decline in hippocampal neurogenesis raises questions about how the function of the dentate gyrus differs between humans and other species in which adult hippocampal neurogenesis is preserved. 链接
Cell Stem Cell文章摘要:
Adult hippocampal neurogenesis declines in aging rodents and primates. Aging humans are thought to exhibit waning neurogenesis and exercise-induced angiogenesis, with a resulting volumetric decrease in the neurogenic hippocampal dentate gyrus (DG) region, although concurrent changes in these parameters are not well studied. Here we assessed whole autopsy hippocampi from healthy human individuals ranging from 14 to 79 years of age. We found similar numbers of intermediate neural progenitors and thousands of immature neurons in the DG, comparable numbers of glia and mature granule neurons, and equivalent DG volume across ages. Nevertheless, older individuals have less angiogenesis and neuroplasticity and a smaller quiescent progenitor pool in anterior-mid DG, with no changes in posterior DG. Thus, healthy older subjects without cognitive impairment, neuropsychiatric disease, or treatment display preserved neurogenesis. It is possible that ongoing hippocampal neurogenesis sustains human-specific cognitive function throughout life and that declines may be linked to compromised cognitive-emotional resilience. 链接
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