阅读难度：

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.

（点击路透社网站查看原文）

衰老与大脑可塑性有关

       据路透社报道，美国研究人员周二发表的一项研究表明，中年人的大脑不如以前灵敏是其一直承受的压力造成的。

       研究人员表示，压力使大脑某一区域用于学习的神经细胞萎缩，失去了可塑能力，即迅速形成神经键的能力。

       该发现有助于进一步理解人的衰老过程，能够解释为什么有些人比其他人衰老得更快。

       领衔此项研究的约翰·莫里森表示，此发现为防治老年痴呆症等大脑衰退病症指出了新的研究途径。

       他说：“如果我们真想了解老年痴呆症，对其进行有效治疗，我们必须采取预防措施，并及早干预。”

(China.org.cn May 26, 2011)