神經(jīng)生物學(xué)科學(xué)家通常將人類的記憶分為三類：陳述性記憶(declarative memory),，如記憶某個(gè)特殊事件,；程序性記憶(procedural memory)，如學(xué)習(xí)彈鋼琴或者灌籃,；工作記憶(working memory),，如短時(shí)記憶一個(gè)電話號(hào)碼等,。
在一項(xiàng)即將發(fā)表于2010年Nature Neuroscience雜志二月版的一項(xiàng)研究報(bào)告中,，凱斯西儲(chǔ)大學(xué)醫(yī)學(xué)院Strowbridge和Larimer等人對(duì)負(fù)責(zé)人類工作記憶的大腦神經(jīng)回路進(jìn)行研究,。
通過分離出老鼠的大腦組織,，研究人員發(fā)現(xiàn)可以在活體內(nèi)建立工作記憶模式,。Larimer對(duì)大腦海馬體中一種稱為mossy細(xì)胞的神經(jīng)元進(jìn)行研究，癲癇病患者通常mossy細(xì)胞發(fā)生受損,。
Mossy細(xì)胞有一個(gè)重要特點(diǎn)——即使在很薄的腦切片中,，Mossy細(xì)胞也能維持正常的活性。當(dāng)研究人員將刺激電極插入到海馬體大腦切片中,，Mossy細(xì)胞自發(fā)的電活性在電極的刺激下被激活,。活體的記憶能夠維持10秒鐘,，這相當(dāng)于人類工作記憶的時(shí)間長(zhǎng)度,。
科學(xué)家測(cè)試了mossy細(xì)胞突觸輸入的頻率，以此來檢驗(yàn)海馬體是否保留了記憶的能力,。據(jù)Strowbridge介紹,，這是首次利用哺乳動(dòng)物大腦組織的腦切片測(cè)試其記憶存儲(chǔ)能力。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature Neuroscience 27 December 2009 | doi:10.1038/nn.2458
Representing information in cell assemblies: persistent activity mediated by semilunar granule cells
Phillip Larimer1 & Ben W Strowbridge1
Here we found that perforant path stimulation in rat hippocampal slices evoked long-lasting barrages of synaptic inputs in subpopulations of dentate gyrus mossy cells and hilar interneurons. Synaptic barrages triggered persistent firing in hilar neurons (hilar up-states). We found that synaptic barrages originate from semilunar granule cells (SGCs), glutamatergic neurons in the inner molecular layer that generate long-duration plateau potentials in response to excitatory synaptic input. MK801, nimodipine and nickel all abolished both stimulus-evoked plateau potentials in SGCs and synaptic barrages in downstream hilar neurons without blocking fast synaptic transmission. Hilar up-states triggered functional inhibition in granule cells that persisted for more than 10 s. Hilar cell assemblies, identified by simultaneous triple and paired intracellular recordings, were linked by persistent firing in SGCs. Population responses recorded in hilar neurons accurately encoded stimulus identity. Stimulus-evoked up-states in the dentate gyrus represent a potential cellular basis for hippocampal working memory.
1 Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA.
