美國布朗大學(xué)的科學(xué)家 在最新一期出刊的PNAS 期刊中，發(fā)表最新的一份研究報(bào)告指出,，透過一項(xiàng)記錄技術(shù)(recording technique) 的發(fā)展,，科學(xué)家成功的錄到大腦不同區(qū)域的對話，因而有可能揭開記憶儲存的秘密,。
長久以來科學(xué)家就對于大腦的記憶模式,，感到高度的興趣,，就過去相關(guān)研究的推論，大腦中不同區(qū)域的功能不同,。就大腦的記憶工作來說,，有的區(qū)域具有短期記憶的功能，有的區(qū)域則被認(rèn)為是儲存記憶的地方,，這次布朗大學(xué) Mayank Mehta教授所主導(dǎo)的研究計(jì)劃,，首先是發(fā)現(xiàn)了睡眠中的腦部電流活動，并非隨機(jī)無規(guī)則的放電,，研究人員利用小鼠的睡眠實(shí)驗(yàn),，確定俗稱海馬回 (hippocampus)的腦部區(qū)域，會緩慢而規(guī)律的向新皮質(zhì) (neocortex)腦區(qū)放出微弱的電流訊號,，而新皮質(zhì)腦區(qū)也會因應(yīng)這些刺激,，發(fā)出一定的響應(yīng)反應(yīng)，來自德國 Max Planck Institute 共同參與這個研究計(jì)劃的Bert Sakmann 博士,，利用新發(fā)展出來的記錄系統(tǒng),，以一個深入新皮質(zhì)腦區(qū)的電極，和3 個分怖于海馬回腦區(qū)的電極,，進(jìn)一步分析這些往返的神經(jīng)電位訊號,，結(jié)果發(fā)現(xiàn)新皮質(zhì)腦區(qū)所發(fā)出的響應(yīng)反應(yīng)和原始的刺激并不相同。
參與的科學(xué)家懷疑這些訊號傳訊的過程,，就像是大腦不同區(qū)域的對話一般,，而這個在睡眠時間發(fā)生的訊號，雖然仍無法了解,，是否跟記憶的儲存有關(guān),，但肯定這是進(jìn)一步了解大腦功能的新方向。
(資料來源 : Bio.com)
部分英文原文：
Published online before print March 12, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0700222104
Differential responses of hippocampal subfields to cortical up-down states
( consolidation | hippocampus | neocortex | oscillation | sleep )
Thomas T. G. Hahn *, Bert Sakmann *, and Mayank R. Mehta
*Department of Cell Physiology, Max Planck Institute for Medical Research, D-69120 Heidelberg, Germany; and Department of Neuroscience, Brown University, Providence, RI 02912
Communicated by Mortimer Mishkin, National Institutes of Health, Bethesda, MD, January 9, 2007 (received for review October 9, 2006)
The connectivity of the hippocampal trisynaptic circuit, formed by the dentate gyrus, the CA3 and the CA1 region, is well characterized anatomically and functionally in vitro. The functional connectivity of this circuit in vivo remains to be understood. Toward this goal, we investigated the influence of the spontaneous, synchronized oscillations in the neocortical local field potential, reflecting up-down states (UDS) of cortical neurons, on the hippocampus. We simultaneously measured the extracellular local field potential in association cortex and the membrane potential of identified hippocampal excitatory neurons in anesthetized mice. Dentate gyrus granule cells showed clear UDS modulation that was phase locked to cortical UDS with a short delay. In contrast, CA3 pyramidal neurons showed mixed UDS modulation, such that some cells were depolarized during the cortical up state and others were hyperpolarized. CA1 pyramidal neurons, located farther downstream, showed consistent UDS modulation, such that when the cortical and dentate gyrus neurons were depolarized, the CA1 pyramidal cells were hyperpolarized. These results demonstrate the differential functional connectivity between neocortex and hippocampal subfields during UDS oscillations.
