2012年11月25日 訊 /生物谷BIOON/ --當(dāng)機體進(jìn)入深睡眠狀態(tài)時,，大腦海馬體會向大腦皮層發(fā)送信息,，并且改變其可塑性,，這或許會轉(zhuǎn)移個體近期獲得性的長期記憶。那么大腦具體是如何完成此項工作的,，近日來自馬普研究所的研究人員開發(fā)出了一種多元的方法,，名為“神經(jīng)事件觸發(fā)的功能性磁共振成像”技術(shù)（NET-fMRI），使用此項技術(shù),，研究者就可以對麻醉,、蘇醒甚至是活動中的猴子進(jìn)行掃描檢測其大腦活性的情況，相關(guān)研究刊登于國際雜志Nature上,。
這種新型技術(shù)使用了多重接觸電極同大腦功能性的磁共振成像相結(jié)合,，來繪制特殊神經(jīng)事件中處于激活狀態(tài)的神經(jīng)元的遍布網(wǎng)絡(luò)。此項研究中,，研究者首次使用這種NET-fMRI技術(shù)來對猴子進(jìn)行檢測,，檢測其大腦海馬體振蕩（形成波紋）活性區(qū)域的活性是處于增加狀態(tài)還是降低狀態(tài)。海馬體的波紋產(chǎn)生一般發(fā)生于深睡眠狀態(tài),，并且可以通過電生理學(xué)方法檢測得到,。使用顱內(nèi)場電位記錄的方法，研究者闡述了短期內(nèi)大腦海馬體波紋不定期循環(huán)發(fā)生和可再生的大腦皮質(zhì)激活密切相關(guān),。
更有意思的是,，大腦內(nèi)激活結(jié)構(gòu)的抑制可以干擾海馬體和大腦皮層之間的交流對話。下丘腦活性的抑制可以減小和感覺過程相關(guān)的信號,。當(dāng)基底核受到抑制后,，大腦橋區(qū)域以及小腦皮層會相抵和記憶系統(tǒng)相關(guān)的信號，比如處于程序性學(xué)習(xí)階段下等情況,。
研究發(fā)現(xiàn)為理解記憶力的大型組織架構(gòu)的形成提供了一定基礎(chǔ),，從神經(jīng)元網(wǎng)絡(luò)的激活到認(rèn)知能力的出現(xiàn)，研究者都可以使用功能性的成像技術(shù)或傳統(tǒng)的單一神經(jīng)元記錄的方法進(jìn)行描述,。感覺能力,、注意力、學(xué)習(xí)能力以及記憶力都可以使用諸如NET-fMRI技術(shù)來進(jìn)行研究分析,，研究這些能力形成的神經(jīng)分子機制對于理解其能力的形成以及發(fā)揮至關(guān)重要,。（生物谷Bioon.com）
編譯自：Neural Interaction in Silence: Neurophysiologists Study Widespread Networks of Neurons Responsible for Memory
doi:10.1038/nature11618
PMC:
PMID:
Hippocampal–cortical interaction during periods of subcortical silence
N. K. Logothetis, O. Eschenko, Y. Murayama, M. Augath, T. Steudel, H. C. Evrard, M. Besserve & A. Oeltermann
Hippocampal ripples, episodic high-frequency field-potential oscillations primarily occurring during sleep and calmness, have been described in mice, rats, rabbits, monkeys and humans, and so far they have been associated with retention of previously acquired awake experience. Although hippocampal ripples have been studied in detail using neurophysiological methods, the global effects of ripples on the entire brain remain elusive, primarily owing to a lack of methodologies permitting concurrent hippocampal recordings and whole-brain activity mapping. By combining electrophysiological recordings in hippocampus with ripple-triggered functional magnetic resonance imaging, here we show that most of the cerebral cortex is selectively activated during the ripples, whereas most diencephalic, midbrain and brainstem regions are strongly and consistently inhibited. Analysis of regional temporal response patterns indicates that thalamic activity suppression precedes the hippocampal population burst, which itself is temporally bounded by massive activations of association and primary cortical areas. These findings suggest that during off-line memory consolidation, synergistic thalamocortical activity may be orchestrating a privileged interaction state between hippocampus and cortex by silencing the output of subcortical centres involved in sensory processing or potentially mediating procedural learning. Such a mechanism would cause minimal interference, enabling consolidation of hippocampus-dependent memory.
