(单词翻译:单击)
听力文本
Researchers Find Clues that Depression May Speed Brain Aging
Memory and thinking skills naturally slow with age. Scientists are now looking inside living brains to tell if depression might speed aging. The scientists report that some of the signs they have found are worrisome.
Depression has long been linked to some cognitive problems. Depression late in life even may increase the risk of developing Alzheimer's disease. Yet how depression might harm the ability to remember things and think clearly is not yet known.
One possibility: Brain cells communicate by sending messages across connections called synapses. Generally, good cognition is linked to more and stronger synapses. With a weakening of cognitive ability, those connections slowly shrink and die. But until recently, scientists could count synapses only in brain tissue collected after the person dies.
Yale University scientists used a new method to study the brains of living people. They discovered that patients with depression had a lower density of synapses than healthy people of the same age.
The lower the density, the more severe the signs of depression. Yale University neuroscientist Irina Esterlis says this is especially true of problems with loss of interest in activities patients once enjoyed. She spoke at a meeting of the American Association for the Advancement of Science.
Esterlis was not studying just older adults, but people of all ages, including those too young for any cognitive changes to be noticeable. She was working from a theory that early damage can build up.
"We think depression might be accelerating the normal aging," she said.
Her studies are small. To prove if depression really does increase the risk of cognitive problems as we age would require more investigation. Jovier Evans is a scientist with the U.S. National Institute of Mental Health. He proposed a study of synaptic density on larger numbers of people as they get older, to see if and how it changes over time in those with and without depression.
Esterlis has announced plans for a larger study to do that. Volunteers would be injected with a radioactive substance that links up to a protein in the vesicles, or storage containers, used by synapses. Then each volunteer would be given an imaging test, known as a PET scan. During the test, areas with synapses light up, enabling researchers to see how many are in different parts of the brain.
Esterlis said there are no medications that target synapse damage.
Doctor Mary Sano directs the Mount Sinai Alzheimer's Disease Research Center in New York. She was not involved in the new research.
Sano warned that normal cognitive aging is a complex process that involves other health problems, such as heart disease. It might be that depression does not worsen synaptic weakening. It could just makes the problem more noticeable, she said.
With depression "at any age, there's a hit on the brain. At an older age the hit may be more visible because there may already be some loss," she explained.
I'm Ashley Thompson.
重点解析
重点讲解：
1. link up to 连接；接合；
The television screens of the next century will be linked up to an emerging world telecommunications grid.
下个世纪的电视屏幕将会接入到正在形成的全球电信网络中。
2. light up 照亮；发亮；
Many shooting stars light up the sky.
许多流星照亮了天空。
3. enable sb. to do sth. 使能够；使有机会；
The software enables you to access the Internet in seconds.
这种软件使你在几秒钟内便可访问互联网。
4. be involved in 卷入的；参与的；与…有密切关联的；
He is still involved in voluntary work promoting local enterprise.
他仍在从事促进当地创业的志愿者工作。
参考译文
研究发现抑郁症会加速大脑老化
记忆力和思维能力会随着年龄的增长而衰退。科学家正在研究活体大脑的内部运作情况，以判断抑郁症是否会加速大脑老化。科学家发表的报告显示，他们发现的一些迹象令人担忧。
抑郁症与一些认知障碍有联系。晚年抑郁症甚至会增加罹患阿兹海默氏症的风险。但是，抑郁症会如何损害记忆力和清晰思维目前尚不得而知。
其中一种可能是：脑细胞通过突触传递信息来进行交流。一般来说，良好的认知能力表明突触数量多且能力强。而认识能力退化说明突触在缓慢退化和消失。但直到最近，科学家还只能在去世者的脑组织中计算突触数量。
耶鲁大学的科学家采用了一种新方法研究活人大脑。他们发现，抑郁症患者的突触密度低于同龄的健康人群。
突触密度越低，抑郁症状越严重。耶鲁大学的神经学家伊琳娜·埃斯特利斯表示，有些患者会对曾经喜欢的活动失去兴趣，对这些人来说这一规律尤为正确。她在美国科学促进会的一场会议上发表了讲话。
埃斯特利斯不仅研究老年人，还对各年龄段人群进行研究，包括那些因为过于年轻而未注意到任何认知改变的人群。她从“早期损害会不断累积”这一理论着手研究。
她说，“我们认为抑郁症可能会加速正常老化。”
她进行的是小型研究。为了证明抑郁症是否确实会随着年龄的增长而增加认知症的风险，需要进行更多调查。乔维尔·埃文斯是美国国家心理健康研究所的科学家。他提议对更多人年龄增长过程中的突触密度进行研究，以观察无抑郁症人群和抑郁症患者的突触密度随着时间的推移是否会发生变化以及会如何变化。
埃斯特利斯宣布将就此展开更大规模的研究。志愿者会被注射一种放射性物质，与囊泡中的蛋白质或突触使用的存储容器相连接。之后，每名志愿者要进行影像检查，即正电子扫描。在检查期间，突触区会亮起来，这使研究人员可以看清楚大脑中不同区域有多少突触。
埃斯特利斯表示，目前没有针对突触损害的药物。
玛丽·萨诺医生是纽约西奈山阿兹海默症研究中心的负责人。她并未参与这项新研究。
萨诺警告称，正常的认知老化是一种复杂的过程，涉及心脏疾病等其他健康问题。抑郁症可能不会加剧突触退化。她说，抑郁症可能只会使这一问题更加明显。
她解释说，“任何年龄层罹患抑郁症都会对大脑造成损害。老年抑郁症可能会更加明显，因为大脑已经开始衰退了。”
阿什利·汤普森报道。
译文为可可英语翻译，未经授权请勿转载！
