近日，美国乔治亚医学院的科学家解码了神经元交流的记忆形成和重唤机制。在实时识别记忆形成和回忆方面的突破性进展为客观全面的记忆研究开辟了一条新的道路，同时也有助于开发更好的疗法。这项研究结果发布在12月16日PLoS ONE上。
在这项研究中，科学家使用了新的技术和计算方法，并结合巴甫洛夫式训练。
在大脑的记忆中枢，研究人员使用128个电极检测神经元的活性，能够同时记录老鼠大脑中200到300个神经元的交流。另外，还结合了巴甫洛夫式训练，即先给老鼠听一个固定的音调，并在20秒后对脚进行轻微的电击。
研究中使用的算法将神经元的活动转化为一种可识别的动态模式，使得科学家能够追踪记忆的形式，比如形成和回忆。通过监听神经元的活性，科学家能够破译神经元实时的动态模式以及交流方式。
虽然每次回忆的时候，踪迹有轻微的改变，这可能是老鼠的情绪和所处的环境变化导致的，但是仍然可以认为是一种特殊的记忆。
研究人员随后进行了老鼠训练行为的记忆重唤。他们发现踪迹与记忆得分紧密相关。低得分的老鼠轨迹暗淡，轨迹越强行为表现越好。
就如研究人员预料的，当老鼠在1小时候后返回原来的训练环境中时，它们就重复表现出呆滞行为，在大脑中的记忆模式被唤醒后。当置于陌生的环境中时，老鼠会在听到声音后出现呆滞行为。该研究一项最令人惊奇的发现是，脚休克的踪迹是单独记忆的。
大脑最基本的认知功能能够在任何水平的学习，巩固，存储，重唤过程中发生。实时观察记忆的形成经有助于寻找记忆问题发生的准确位点，并进行更多的靶向研究和治疗。（生物谷Bioon.com）
相关运用巴甫洛夫式训练的实验：
Nature：微生物的主动应对行为
Current Biology：果蝇实验显示群体环境更有利于记忆
Nature：多巴胺神经元的复杂性
生物谷推荐原始出处：
PLoS ONE 4(12): e8256. doi:10.1371/journal.pone.0008256
Neural Population-Level Memory Traces in the Mouse Hippocampus
Guifen Chen, L. Phillip Wang, Joe Z. Tsien*
Brain and Behavior Discovery Institute and Department of Neurology, School of Medicine, Medical College of Georgia, Augusta, Georgia, United States of America
One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial.
