人們常常會想：人的大腦到底被利用了百分之多少？美國科學(xué)家的一項最新研究確定了大腦分配細胞進行編碼和記憶存儲的關(guān)鍵機制——一種名為CREB的蛋白,。在這種蛋白影響下,，人類中腦只有20%的神經(jīng)細胞用于形成記憶。該研究成果為治療阿爾海默癥等腦部疾病開辟了新的道路,。相關(guān)論文發(fā)表在4月20日的《科學(xué)》雜志上。
美國加州大學(xué)洛杉磯分校和加拿大多倫多大學(xué)的科學(xué)家的聯(lián)合研究發(fā)現(xiàn),，這種CREB蛋白控制著大腦中神經(jīng)元參與記憶形成的幾率,。
加州大學(xué)洛杉磯分校 David Geffen醫(yī)學(xué)院神經(jīng)生物學(xué)家和精神病專家、該研究項目負責(zé)人Alcino Silva表示,，“記憶的產(chǎn)生并不是有意識的行為,，而是人們通過學(xué)習(xí)激發(fā)大腦產(chǎn)生一系列化學(xué)物質(zhì)，從而影響記憶的產(chǎn)生,、維持和喪失,。”
此前的研究已經(jīng)表明，CREB蛋白對于維持記憶的穩(wěn)定有重要意義,。Silva表示,，“我們猜測CREB在引導(dǎo)大腦細胞的記憶存儲上，也起著至關(guān)重要的作用,。”
通過對小鼠模型進行研究,，Silva和同事來驗證了他們的假設(shè)。研究人員先將CREB蛋白轉(zhuǎn)入一種病毒,，而后將該病毒導(dǎo)入小鼠大腦杏仁核區(qū)域（amygdala,，大腦中的重要的情感記憶區(qū)域）的一些神經(jīng)細胞,。隨后，科學(xué)家測定了小鼠回憶起自己籠子的能力,，這種籠子具有特定圖案的墻壁和獨特的氣味,。
為了更加直觀地了解哪些大腦細胞存儲著小鼠的記憶，科學(xué)家追蹤了一種“遺傳標(biāo)記”,，以揭示神經(jīng)元的活動,。研究人員最終發(fā)現(xiàn)，神經(jīng)細胞中CREB的數(shù)量影響著該細胞是否被用于存儲記憶,。Silva說,，“如果細胞中的CREB含量較低，那么它保存記憶的可能性就??；反之，該細胞更有可能存儲記憶,。”
這一最新研究成果對于人類具有深遠的意義,。Silva表示，“通過人工控制大腦神經(jīng)細胞中CREB蛋白的含量,，我們將能夠決定大腦存儲記憶的位置,。這種方法有望被用于保護阿爾海默癥等大腦疾病患者的記憶。我們有可能引導(dǎo)記憶從大腦瀕死區(qū)域的病態(tài)神經(jīng)細胞進入其他位置的健康神經(jīng)細胞,。”
原始出處:
Science 20 April 2007:
Vol. 316. no. 5823, pp. 457 - 460
DOI: 10.1126/science.1139438
Reports
Neuronal Competition and Selection During Memory Formation
Jin-Hee Han,1,2,3* Steven A. Kushner,4,5,6* Adelaide P. Yiu,1,3 Christy J. Cole,1,2 Anna Matynia,4 Robert A. Brown,4 Rachael L. Neve,7 John F. Guzowski,8 Alcino J. Silva,4 Sheena A. Josselyn1,2,3
Competition between neurons is necessary for refining neural circuits during development and may be important for selecting the neurons that participate in encoding memories in the adult brain. To examine neuronal competition during memory formation, we conducted experiments with mice in which we manipulated the function of CREB (adenosine 3',5'-monophosphate response element–binding protein) in subsets of neurons. Changes in CREB function influenced the probability that individual lateral amygdala neurons were recruited into a fear memory trace. Our results suggest a competitive model underlying memory formation, in which eligible neurons are selected to participate in a memory trace as a function of their relative CREB activity at the time of learning.
1 Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
2 Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
3 Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
4 Departments of Neurobiology, Psychology, and Psychiatry, and Brain Research Institute, Gonda Building, 695 Young Drive South, University of California, Los Angeles, CA 90095, USA.
5 Department of Psychiatry, Columbia University, New York, NY 10032, USA.
6 New York State Psychiatric Institute, New York, NY 10032, USA.
7 Molecular Neurogenetics Laboratory, Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, MA 02478, USA.
8 Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, CA 92697, USA.
* These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail: [email protected]
