Representation, Storage, and Decay in Auditory-Verbal Working Memory

提出的研究的总体目标是显著推进我们对言语工作记忆的神经机制的理解。几十年来对言语工作记忆认知心理学的研究表明，人们记住言语信息的主要方式是通过声下排练，或内心言语。换句话说，为了保持语言信息在意识中的高度，我们利用了我们与自己进行内部对话的能力。在Baddeley和同事的经典语言工作记忆模型中，语音回路，内部言语被分解为两个交流组件：一个运动/发音过程和一个语音/听觉组件。在过去的20年里，认知神经科学试图理解这两个组成部分是如何“映射”到大脑的。然而，我们对言语工作记忆的机制基础仍然知之甚少。因此，虽然我们知道在言语信息的在线维护过程中，运动/听觉皮层区域都是“活跃的”，但我们对这些区域进行的计算却知之甚少。在这个建议中，我们使用一系列的功能性磁共振成像（fMRI）研究来阐明语言记忆是在大脑的听觉皮层编码的。随着多体素模式分析（MVPA）技术的出现，现在可以捕获和可靠地识别特定刺激或认知状态编码的神经激活的分布模式。在这里，我们利用功能磁共振成像技术的非凡发展来“解码”听觉皮层在听觉记忆检索和内心语言中表现出来的活动模式。首先，我们将检验由外部和内部言语所诱发的活动模式在听觉皮层中具有表征基础的假设。其次，我们将测试一个关于内在言语的重要说法，该说法表明，它是运动到感觉放电的结果，而运动到感觉放电是内部监测电路的一部分，对语音产生中的纠错很重要。最后，我们将研究感知语言的“表面特征”，如性别和口音，是如何被纳入工作记忆中激活的听觉记忆痕迹的。***虽然这个建议的重点是在听觉-言语模式，但其含义超出了这个“模型子系统”，因为我们从当前的一组实验中学到的东西将与其他记忆领域相关并适用。此外，这项工作的一个关键目标是继续追求一套统一的原则，这些原则是不同类型记忆的存储、表征和激活的基础，包括言语、视觉空间、短期和长期、情景和语义。因此，这项工作是一个更大的跨越职业生涯的项目的一部分，该项目的长期目标是设计一种更连贯、更少划分的对人类记忆的理解

The overarching goal of the proposed research is to significantly advance our understanding of the neural mechanisms underlying verbal working memory. Decades of research on the cognitive psychology of verbal working memory have shown that the primary way in which people keep verbal information in mind is through subvocal rehearsal, or inner speech. In other words, to keep verbal information aloft in consciousness we make use of our capacity to carry on an internal conversation with ourselves. In Baddeley and colleagues' classic model of verbal working memory, the phonological loop, inner speech is decomposed into two communicating components: a motor/articulatory process and a phonological/auditory component. In the last 20 years, cognitive neuroscience has tried to understand how these two components "map" on to the brain. However, we still have a poor understanding of the mechanistic basis of verbal working memory. Thus, while we know that during the online maintenance of verbal information both motor/ and auditory cortical areas are "active", we have a poor of the computations carried out by these regions.***In this proposal we use a series of functional magnetic resonance imaging (fMRI) studies to elucidate memories for speech are coded in the brain's auditory cortex. With the advent of multivoxel pattern analysis (MVPA) techniques, it is now possible to capture and reliably identify distributed patterns of neural activation that code for particular stimuli or cognitive states. Here we take advantage of this extraordinary development in fMRI technology to "decode" the patterns of activity in auditory cortex that are manifested during auditory memory retrieval and inner speech. First, we will test the hypothesis that patterns of activity evoked by external and inner speech share a representational basis in auditory cortex. Second, we will test a prominent account of inner speech that suggests that it emerges as a result of motor-to-sensory discharges that are part of an internal monitoring circuit important for error correction in speech production. Last, we will investigate how "surface features" of perceived speech, such as gender and accent, are incorporated into the auditory memory traces that are activated during working memory.***Although the focus of this proposal is in the auditory-verbal modality, the implications go beyond this "model subsystem" because the what we learn from the current set of experiments will be relevant and applicable to other memory domains. Furthermore, a key aim of this work is to continue to pursue a set of unifying principles that underlie the storage, representation, and activation of different kinds of memory, including verbal, visuospatial, short- and long-term, episodic and semantic. This work, therefore, is part of a larger career-spanning program with the long-term goal of devising a more coherent and less compartmentalized understanding of human memory.**