閱讀難度：

A study released Tuesday by US researchers showed that the middle-aged brain is not as nimble as it used to be because of all the stress it has endured, Reuters reports.

The researchers said stress causes nerve cells in a part of the brain needed for learning to shrink and lose plasticity -- the ability to quickly form connections called synapses.

The findings add new understanding to the process of aging and may help explain why some people decline more quickly than others.

John Morrison, who led the study, said the findings point to a new approach in the search for treatments that protect the brain from age-related declines, such as in Alzheimer's disease.

"If we really want to understand Alzheimer's disease and deal with it effectively, we have to prevent it. And preventing it will require very early intervention," he said.

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衰老與大腦可塑性有關

???????據路透社報道，美國研究人員周二發表的一項研究表明，中年人的大腦不如以前靈敏是其一直承受的壓力造成的。

???????研究人員表示，壓力使大腦某一區域用于學習的神經細胞萎縮，失去了可塑能力，即迅速形成神經鍵的能力。

???????該發現有助于進一步理解人的衰老過程，能夠解釋為什么有些人比其他人衰老得更快。

???????領銜此項研究的約翰·莫里森表示，此發現為防治老年癡呆癥等大腦衰退病癥指出了新的研究途徑。

???????他說：“如果我們真想了解老年癡呆癥，對其進行有效治療，我們必須采取預防措施，并及早干預。”

(China.org.cn May 26, 2011)