日常生活中人们常常会有要短时间记住新电话号码或初识者姓名这样的短期记忆需求。德国和英国科学家最近报告说，他们首次用科学测量证实人脑是通过不断“回放”需记忆的信息来强化短期记忆的。
德国马格德堡大学日前发表公报说，科学界一直猜测保持短期记忆是通过人脑对信息的不断复述实现的，但是这一猜测一直没有得到科学证实，原因是以很高的时间精度“破译”人脑活动在技术上存在很大难度。马格德堡大学和伦敦大学学院的研究人员最近做到了这一点。
他们首先用脑磁图仪记录下了一些实验对象在短期记忆风景照片细节时的脑部活动，随后又用一种“多元模式分类器译码算法”破译了这些脑部活动代表的信息，进而证实实验对象在努力进行短期记忆时，有关照片信息在脑中被不断“回放”。
研究人员说，他们研发的这种以很高的时间精度“破译”人脑活动内容的方法是一项技术突破，有助于深入了解记忆障碍的原因。
这一成果已被美国《当代生物学》（Current Biology）杂志发表。
更多阅读
《当代生物学》发表论文摘要（英文）
Current Biology, Volume 20, Issue 7, 606-612, 18 March 2010 | Copyright 2010 Elsevier Ltd All rights reserved. | 10.1016/j.cub.2010.01.057
Theta-Coupled Periodic Replay in Working Memory
Lluís Fuentemilla, Will D. Penny, Nathan Cashdollar, Nico Bunzeck, Emrah Düzel
Summary
Working memory allows information from transient events to persist as active neural representations [1] that can be used for goal-directed behaviors such as decision making and learning [2,3]. Computational modeling based on neuronal firing patterns in animals suggests that one putative mechanism enabling working memory is periodic reactivation (henceforth termed replay) of the maintained information coordinated by neural oscillations at theta (48 Hz) and gamma (3080 Hz) frequency [4,5,6]. To investigate this possibility, we trained multivariate pattern classifier decoding algorithms on oscillatory brain responses to images depicting natural scenes, recorded with high temporal resolution via magnetoencephalography. These classifiers were applied to brain activity recorded during the subsequent five second maintenance of the scenes. This decoding revealed replay during the entire maintenance interval. Replay was specific to whether an indoor or an outdoor scene was maintained and whether maintenance centered on configural associations of scene elements or just single scene elements. Replay was coordinated by the phase of theta and the amount of theta coordination was correlated with working memory performance. By confirming the predictions of a mechanistic model and linking these to behavioral performance in humans, these findings identify theta-coupled replay as a mechanism of working memory maintenance.
