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One of the first signs of Alzheimer’s disease is confusion.
阿尔茨海默病的最初症状之一是神志不清。
Most people can park their car in a different space every morning and find it again in the evening.
大多数人可以每天早上把车停在不同的地方，晚上再找到它。
Those with Alzheimer’s find this type of problem much harder.
那些患有老年痴呆症的人会发现这类问题要困难得多。
Memories of things they do often, like eating or taking medication, become tangled in their minds.
他们记忆中经常做的事情，比如吃饭或服药，在脑海中变得纠结复杂。
The ability to distinguish between similar memories depends on a tiny strip of brain tissue called the dentate gyrus.
区分相似记忆的能力依赖于一小块被称为齿状回的脑组织。
Studies in mice have shown that the dentate gyrus is one of the few bits of the brain to generate new neurons even in adulthood.
对老鼠的研究表明，即使在成年后，齿状回也是大脑中少数几个会产生新神经元的部位之一。
Those new neurons are thought to help keep similar memories distinct.
这些新的神经元被认为有助于保持相似记忆的区别。
Whether something similar happens in humans is less clear.
尚不清楚人类是否也会发生类似的情况。
But a clutch of new results described this week at the Society for Neuroscience’s conference in Washington, dc, suggest that it might.
但本周在华盛顿举行的神经科学学会会议上公布的一系列新结果表明，答案可能是肯定的。
And if it does, then encouraging the process might offer a new treatment for Alzheimer’s disease.
如果确实如此，那么促进这个过程可能会为阿尔茨海默病提供一种新的治疗方法。
Until the 1960s scientists thought adult brains did not produce new neurons.
直到20世纪60年代，科学家们都认为成年人的大脑不会产生新的神经元。
Then evidence began to emerge of young neurons in the brains of adult rats and mice,—specifically in the olfactory bulb, which processes smell, and the dentate gyrus.
随后，成年大鼠和小鼠的大脑中出现了年轻神经元的证据，特别是在处理气味的嗅球和齿状回中。
These new neurons had developed from neural progenitor cells, a type of undifferentiated neuron akin to a stem cell, in a process scientists call neurogenesis.
这些新神经元是从神经祖细胞(一种类似于干细胞的未分化神经元)发育而来的，科学家们将这一过程称为神经发生。
And there seems to be a link, at least in mice, between these new neurons and Alzheimer’s disease.
至少在老鼠身上，这些新神经元和阿尔茨海默病之间似乎存在联系。
Mice genetically engineered to have Alzheimer’s-like symptoms also have fewer young neurons in their brains.
经过基因改造后出现类似阿尔茨海默病症状的老鼠，大脑中年轻的神经元也更少了。
Two studies published in 2021 and 2022 showed that encouraging neurogenesis could improve memory in such animals.
2021年和2022年发表的两项研究表明，促进神经发生可以改善这些动物的记忆力。
And a paper published in April this year found that boosting neurogenesis also caused other cells known as microglia to begin cleaning up tangles of protein, called amyloid-beta plaques, that are characteristic of Alzheimer’s disease.
今年4月发表的一篇论文发现，促进神经发生也会导致其他小胶质细胞，开始清理淀粉样蛋白斑块的蛋白质缠结，这是阿尔茨海默病的特征。
So far so promising—if you are a mouse.
到目前为止，一切都很有希望——如果你是一只老鼠的话。
But studying neurogenesis in humans is tricky.
但是研究人类的神经发生是很棘手的。
mri scanners cannot watch the growth of individual neurons.
核磁共振扫描仪不能观察单个神经元的生长。
Scientists must take samples of brain tissue from cadavers and either stain them with chemicals that bind only to young neurons, or measure the genes that have been expressed within brain cells to look for the hallmarks of youth.
科学家们必须从尸体上采集脑组织样本，要么用只与年轻神经元结合的化学物质染色，要么测量脑细胞中表达的基因，以寻找年轻神经元的特征。
