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新研究显示，咖啡通过刺激额前叶皮层来增进短期记忆加速反应次数。
研究人员使用功能磁效应成像(fMRI)在十五个志愿者身上研究咖啡如何激活脑不同的区域。
在奥地利因斯布鲁克市医药大学，Florian Koppelstatter和同事一起进行研究，她说：“咖啡因通过作用于脑不同的区域来调节更高级的大脑功能。”
在实验之前，小组禁食4～6个小时，禁止咖啡因和尼古丁至少24个小时.然后分给他们每人或一杯浓咖啡—包含100微克的咖啡因-或无咖啡因的安慰剂.20分钟后所有的参与者进行记忆力和集中力测试，接受fMRI扫描。几天之后在相同的情况下重复试验，不同的是受试者换了另一种饮料。
执行记忆力
在记忆里测试中，参予者被示以快速序列大写字母，然后在屏幕上闪现单字母让受试者快速判断是否与早先出现的的序列中的第二个到最后一个相同。他们必须选择按Y表示正确，按N表示不正确。
“整个小组都显示出大脑工作记忆的激活，”Koppelstatter 解释到：“但是接受咖啡的显示出更强的额前叶活性，包括前带和前脑回。这些区域参予“执行记忆力”，注意力，集中力，计划和监控。”
他补充道：“这种记忆用于当你注视电话簿上的号码然后在拨出之前进行储存。”
提神饮料
Koppelstatter强调研究仍处在初步并且他说他必须发现记忆效果可以持续多长时间或咖啡对脑功能起到的其他作用。他补充道长时间的咖啡因使用的影响同样是一个重要的考虑问题。
但是他说，研究显示咖啡在记忆力和集中力的特殊脑区域产生作用，这与饮料的提神效果相一致。
咖啡因被认为影响腺苷受体，腺苷受体贯穿大脑的神经细胞和毛细血管。据认为药品抑制这些受体，并且这些受体刺激大脑神经细胞。“这可能正是内涵的机制。”Koppelstatter推测。
此研究发表于南美放射学协会年会。
Coffee's effects revealed in brain scans
10:56 01 December 2005
NewScientist.com news service
Gaia Vince
Coffee improves short-term memory and speeds up reaction times by acting on the brain’s prefrontal cortex, according to a new study.
Researchers used functional magnetic resonance imaging (fMRI) to determine how coffee activates different areas of the brain in 15 volunteers.
“Caffeine modulates a higher brain function through its effects on distinct areas of the brain,” explains Florian Koppelstätter, who carried out the research with colleagues at the Medical University at Innsbruck, Austria.
Prior to testing, the group fasted for 4 to 6 hours, and abstained from caffeine and nicotine for at least 24 hours. Then they were then given either a cup of strong coffee – containing 100 milligrams of caffeine – or a caffeine-free placebo drink. After 20 minutes all participants underwent fMRI scans while carrying out a memory and concentration test. A few days afterwards the experiment was repeated under the same conditions but each received the other drink.
Executive memory
During the memory tests, participants were shown a fast sequence of capital letters, then flashed a single letter on a screen and told to decide quickly whether this letter was the same as the one which appeared second-to-last in the earlier sequence. They had to respond by pressing a “Y” for yes or “N” for no.
“The group all showed activation of the working memory part of the brain," Koppelstätter explains. "But those who received caffeine had significantly greater activation in parts of the prefrontal lobe, known as the anterior cingulate and the anterior cingulate gyrus. These areas are involved in 'executive memory', attention, concentration, planning and monitoring."
“This type of memory is used when, for example, you look up a telephone number in a book and then mentally store it before dialling,” he adds.
Pick-me-up
Koppelstätter stresses that the study is preliminary and that he has yet to discover how long the memory effects last or what other effects coffee has on brain function. He adds that the long-term impact of caffeine use is also an important consideration.
But he says the study shows that coffee has an effect on specific brain regions involved in memory and concentration that tallies with anecdotal evidence of the drink's “pick-me-up” effect.
Caffeine is known to influence adenosine receptors which are found throughout the brain on nerve cells and blood vessels. It is thought that the drug inhibits these receptors and that this excites the nerve cells in the brain. “This may be the mechanism involved,” suggests Koppelstätter.
The research was presented at the annual meeting of the Radiological Society of North America.
帖子在2005-12-30 14:47:47被编辑过了 | 最初发表时间：2005-12-30 |  | 黄沙百战穿金甲 不破楼兰终不还
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