美国斯坦福大学Tirin Moore等研究人员合作发现，间歇性速率编码和特定提示的神经元群体支持工作记忆。2024年11月6日，《自然》杂志在线发表了这项成果。

研究人员表示，长期以来，人们假设持续的、特定记忆的神经元放电活动是工作记忆的基础。然而，越来越多的证据表明，“活动静默”的突触机制可能也起着作用。这一问题仍然存在争议，因为支持任一观点的证据主要依赖于无法捕捉单次试验人口动态的数据集，或是间接测量神经元放电的方式。

研究人员通过在执行工作记忆任务的猴子中，同时记录大量侧前额叶神经元的单次试验数据，解决了这一争议。研究人员表明，在记忆延迟期间，记忆信息并不会在神经元群体的放电活动中持续存在，而是交替在协调的“开”和“关”状态之间切换。

在单个神经元层面上，“关”状态由两部分因素驱动：一是记忆内容选择性的丧失，二是放电速率回归到自发水平。进一步利用大规模记录数据，研究人员发现，在“关”状态下，神经元群体之间的功能连接模式中仍然包含记忆信息。

这些结果表明，特定记忆内容的间歇性放电与突触机制共同作用以支持工作记忆。

附：英文原文

Title: Intermittent rate coding and cue-specific ensembles support working memory

Author: Panichello, Matthew F., Jonikaitis, Donatas, Oh, Yu Jin, Zhu, Shude, Trepka, Ethan B., Moore, Tirin

Issue&Volume: 2024-11-06

Abstract: Persistent, memorandum-specific neuronal spiking activity has long been hypothesized to underlie working memory1,2. However, emerging evidence suggests a potential role for ‘activity-silent’ synaptic mechanisms3,4,5. This issue remains controversial because evidence for either view has largely relied either on datasets that fail to capture single-trial population dynamics or on indirect measures of neuronal spiking. We addressed this controversy by examining the dynamics of mnemonic information on single trials obtained from large, local populations of lateral prefrontal neurons recorded simultaneously in monkeys performing a working memory task. Here we show that mnemonic information does not persist in the spiking activity of neuronal populations during memory delays, but instead alternates between coordinated ‘On’ and ‘Off’ states. At the level of single neurons, Off states are driven by both a loss of selectivity for memoranda and a return of firing rates to spontaneous levels. Further exploiting the large-scale recordings used here, we show that mnemonic information is available in the patterns of functional connections among neuronal ensembles during Off states. Our results suggest that intermittent periods of memorandum-specific spiking coexist with synaptic mechanisms to support working memory.

DOI: 10.1038/s41586-024-08139-9

Source: https://www.nature.com/articles/s41586-024-08139-9