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原子弹帮助确认成人的大脑确实产生新的神经元

发布日期:2018-09-16 作者:admin

A long-time assumption in the medical world is that mature, differentiated neurons do not divide and that they’;re formed during the embryonic development stage。 This does not necessarily mean, however, that all neurons are grown during this stage only and that they do not form during adulthood as well。 Proving that neurons can form during adulthood is a difficult task however since there isn’;t a way to date new neurons and thus tell them apart from those formed when we were born。 A new study published in the journal Cell describes a new method that dates the birth of neurons by measuring elevated atmospheric levels of carbon-14, a nonradioactive form of carbon, caused by above-ground nuclear bomb testing more than 50 years ago。

“It was thought for a long time that we are born with a certain number of neurons, and that it is not possible to get new neurons after birth,” says senior study author Jonas Frisén of the Karolinska Institute。

Carbon-14 nuclear testSince surface nuclear tests have been banned in 1960s, atmospheric levels of the carbon-14 isotope have declined with a known-rate, still this heavy carbon remains in the atmosphere to this day and becomes ingested along with normal carbon whenever we eat plants or animal products。 As such, it becomes absorbed by our bodies and  the exact atmospheric concentration at any point in time is stamped into DNA every time a new neuron is born。 Remarkably, this allows for carbon-dating neurons much in the same manner archaeologists determine the age of an ancient urn。

To test their method, the researchers carbon-dated neurons from the brains of deceased individuals。 Their findings show that some 1,400 new neurons in the dentate gyrus area are added each day corresponding to an annual turnover of 1。75% of the neurons within the renewing fraction, with a modest decline during aging。

本文源自: AG环亚官网

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