美国西奈医疗中心Ueli Rutishauser、Jonathan Daume小组近日取得一项新成果。经过不懈努力，他们发现人类海马神经元的相位-振幅耦合调控工作记忆。这一研究成果发表在2024年4月17日出版的国际学术期刊《自然》上。

研究人员发现额叶控制和海马持久性活动之间的相互作用是通过θ-γ相位-振幅耦合（TG-PAC）实现的。在保留多个项目工作记忆的患者中，研究人员记录了人内侧颞叶和额叶的单个神经元活动。在海马体中，TG-PAC可表征工作记忆的负荷和质量。研究发现在θ相位和γ振幅的非线性相互作用过程中会选择性出现尖峰细胞。当认知控制需求较高时，这些PAC神经元的尖峰时间与额叶θ活动相协调。

通过引入与海马中持续活跃神经元的噪声相关性，PAC神经元塑造了群体代码的几何形状。这使得工作记忆内容的表征保真度更高，并与行为改善相关。该研究结果支持工作记忆的多组分结构，工作记忆内容在存储相关区域的维持由额叶控制。在这一框架内，海马TG-PAC将认知控制和工作记忆存储整合到大脑的各个区域，从而揭示了一种自上而下调控感觉驱动的潜在机制。

据介绍，保留工作记忆中的信息是一个要求很高的过程，需要依靠认知控制来保护特定记忆的持续活动不受干扰。然而，尚不清楚认知控制如何调节工作记忆的存储。

附：英文原文

Title: Control of working memory by phase–amplitude coupling of human hippocampal neurons

Author: Daume, Jonathan, Kamiski, Jan, Schjetnan, Andrea G. P., Salimpour, Yousef, Khan, Umais, Kyzar, Michael, Reed, Chrystal M., Anderson, William S., Valiante, Taufik A., Mamelak, Adam N., Rutishauser, Ueli

Issue&Volume: 2024-04-17

Abstract: Retaining information in working memory is a demanding process that relies on cognitive control to protect memoranda-specific persistent activity from interference1,2. However, how cognitive control regulates working memory storage is unclear. Here we show that interactions of frontal control and hippocampal persistent activity are coordinated by theta–gamma phase–amplitude coupling (TG-PAC). We recorded single neurons in the human medial temporal and frontal lobe while patients maintained multiple items in their working memory. In the hippocampus, TG-PAC was indicative of working memory load and quality. We identified cells that selectively spiked during nonlinear interactions of theta phase and gamma amplitude. The spike timing of these PAC neurons was coordinated with frontal theta activity when cognitive control demand was high. By introducing noise correlations with persistently active neurons in the hippocampus, PAC neurons shaped the geometry of the population code. This led to higher-fidelity representations of working memory content that were associated with improved behaviour. Our results support a multicomponent architecture of working memory1,2, with frontal control managing maintenance of working memory content in storage-related areas3,4,5. Within this framework, hippocampal TG-PAC integrates cognitive control and working memory storage across brain areas, thereby suggesting a potential mechanism for top-down control over sensory-driven processes.

DOI: 10.1038/s41586-024-07309-z

Source: https://www.nature.com/articles/s41586-024-07309-z