文章来源:未知 文章作者:enread 发布时间:2011-03-21 03:18 字体: [ ]  进入论坛

You may remember the color of your loved one's eyes for years. But how? Scientists believe that long-term potentiation(增强作用) (LTP) – the long-lasting1 increase of signals across a connection between brain cells -- underlies2 our ability to remember over time and to learn, but how that happens is a central question in neuroscience.

Researchers at Duke University Medical Center have found a cascade3(层叠,小瀑布) of signaling molecules4 that allows a usually very brief signal to last for tens of minutes, providing the brain framework for stronger connections (synapses6) that can summon a memory for a period of months or even years.

Their findings about how the synapses change the strength of connections could have a bearing on Alzheimer's disease, autism and mental retardation7(智力迟钝) , said Ryohei Yasuda, Ph.D., assistant professor of neurobiology and senior author.

"We found that a biochemical process that lasts a long time is what causes memory storage," said Yasuda, who is a Howard Hughes Medical Institute Early Career Scientist.

This work was published in the March 20 issue of Nature.

The researchers were investigating the signaling molecules that regulate the actin cytoskeleton(细胞骨架) , which serves as the structural8 framework of synapses.

"The signaling molecules could help to rearrange the framework, and give more volume and strength to the synapses," Yasuda said. "We reasoned that a long-lasting memory could possibly come from changes in the building block assemblies."

The Duke researchers knew that long-term potentiation, a long-lasting set of electrical impulses in nerve cells, is triggered by a transient(短暂的,路过的) increase of calcium9 (Ca2+) ions in a synapse5. They devised experiments to learn exactly how the short Ca2+ signal, which lasts only for ~0.1s, is translated into long-lasting (more than an hour) change in synaptic transmission.

The team used a 2-photon microscopy technique to visualize10 molecular11 signaling within single synapses undergoing LTP, a method developed in the Yasuda lab. This microscopy method allowed the team to monitor molecular activity in single synapses while measuring the synapses for increase in their volume and strength of the connections.

They found that signaling molecules Rho and Cdc42, regulators of the actin cytoskeleton, are activated12 by CaMKII, and relay a CaMKII signal into signals lasting many minutes. These long-lasting signals are important for maintaining long-lasting plasticity of synapses, the ability of the brain to change during learning or memorization.

Many mental diseases such as mental retardation and Alzheimer's disease are associated with abnormal Rho and Cdc42 signals, Yasuda said. "Thus, our finding will provide many insights into these diseases."


1 lasting IpCz02     
  • The lasting war debased the value of the dollar.持久的战争使美元贬值。
  • We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。
2 underlies d9c77c83f8c2ab289262fec743f08dd0     
v.位于或存在于(某物)之下( underlie的第三人称单数 );构成…的基础(或起因),引起
  • I think a lack of confidence underlies his manner. 我认为他表现出的态度是因为他缺乏信心。 来自《简明英汉词典》
  • Try to figure out what feeling underlies your anger. 努力找出你的愤怒之下潜藏的情感。 来自辞典例句
3 cascade Erazm     
  • She watched the magnificent waterfall cascade down the mountainside.她看着壮观的瀑布从山坡上倾泻而下。
  • Her hair fell over her shoulders in a cascade of curls.她的卷发像瀑布一样垂在肩上。
4 molecules 187c25e49d45ad10b2f266c1fa7a8d49     
分子( molecule的名词复数 )
  • The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
5 synapse 3HrzM     
  • The chemical floods the synapse, overwhelming the serotonin receptors.这种化学物质湮没了突触,覆盖了5--羟色胺的受体。
  • Ecstasy also keeps serotonin from being reabsorbed,further increasing the concentration in the synapse.毒品引起的狂迷还能阻止5--羟色胺的再吸收,进一步增加了突触内5--羟色胺的浓度。
6 synapses 866e8ec5e7e57c04ff0daa7921c4d2a5     
n.(神经元的)突触( synapse的名词复数 );染色体结合( synapsis的名词复数 );联会;突触;(神经元的)触处
  • Nerve cells communicate with one another at the synapses, where their membranes almost touch. 神经细胞在突触部位彼此沟通,在这里它们的膜几乎接触到一起了。 来自辞典例句
  • Glutamatergic synapses are common excitatory chemical connections in mammalian central nervous system. 谷氨酸性突触是哺乳动物神经系统的主要兴奋性突触。 来自互联网
7 retardation zjZzyh     
  • Asbestos reinforcement confers excellent flame retardation properties on a composite. 石棉增强材料使复合材料具有优异的防火性能。
  • The theory confirms the increase in the retardation effect with decrease in particle size. 理论证实,随着颗粒尺寸的减小,这一减速效应将增大。
8 structural itXw5     
  • The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
9 calcium sNdzY     
  • We need calcium to make bones.我们需要钙来壮骨。
  • Calcium is found most abundantly in milk.奶含钙最丰富。
10 visualize yeJzsZ     
  • I remember meeting the man before but I can't visualize him.我记得以前见过那个人,但他的样子我想不起来了。
  • She couldn't visualize flying through space.她无法想像在太空中飞行的景象。
11 molecular mE9xh     
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
12 activated c3905c37f4127686d512a7665206852e     
adj. 激活的 动词activate的过去式和过去分词
  • The canister is filled with activated charcoal.蒸气回收罐中充满了活性炭。
TAG标签: cells brain memory