人類大腦記憶中心在13歲時就停止生長大綱

New neurons stop growing in a key region of the brain's 'memory center' as early as 13 years old, according to a controversial new study.

一項有爭議的新研究顯示，早在人類13歲時，大腦“記憶中心”的關鍵區域，新神經元就已經停止生長了。

Scientists looking at brain tissue samples found no evidence of new nerve cell growth in the dentate gyryus, a part of the hippocampus vital to memory formation, after the age of 13.

研究腦組織樣本的科學家沒有發現人類在13歲後齒狀回（海馬區的一個部分）中有新神經細胞生長的證據。海馬區對於記憶的形成至關重要。

The discovery contradicts previous findings suggesting that hippocampal neurons replenish themselves throughout adulthood, as they do in many other mammals.

這一發現與之前的研究結果相矛盾，以往的研究顯示，人類大腦海馬區的神經元在整個成年時期都會不斷自我補充，就像它們在其他哺乳動物身上一樣。

New hippocampus neuron development also dwindled over time in macaque monkeys, the scientists found. And hippocampus regeneration was thought to be lacking in big-brained dolphins, porpoises and whales.

科學家們發現，在獼猴身上，新海馬神經元的發育也逐漸減少。而海豚和鯨魚則被認爲缺乏海馬體的再生。

Writing in the journal Nature, the authors led by Dr Arturo Alvarez-Buylia, from the University of California at San Francisco, concluded: 'Neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans.'

該研究由加利福尼亞大學舊金山分校的阿圖羅·阿爾瓦雷斯-拜利亞博士領導，發表在英國《自然》週刊上。該文章總結道，“在成年人中，齒狀回中的神經元再生不會繼續，或者非常罕見。”

'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.'

“海馬區神經再生的早期衰退提出了人類和其他物種之間齒狀回功能如何不同的問題。其他物種在成年期仍可再生海馬神經元。”

In an accompanying News And Views commentary, Dr Jason Snyder from the University of British Columbia, Canada, wrote: 'These findings are in stark contrast to the prevailing view that human hippocampal neurogenesis extends throughout adult life.'

加拿大英屬哥倫比亞大學的傑森·斯奈德博士在一篇相關的新聞與觀察評論中寫道：“這些發現與人們普遍認爲的人類海馬神經發生貫穿成年期的觀點形成了鮮明的對比。”