Feedback and Feedforward Mechanisms of Speech Perception

摘要/项目总结 言语交际在向他人传达我们的思想、保持社会联系以及 支持教育成就。因此，影响言语感知的沟通障碍， 孤独症、阅读障碍和听力损失对个人和社会都是代价高昂的。了解神经生物学 语音处理的基础是一个重要的目标，已经加快了侵入性颅内电生理学 在神经外科领域。然而，大量的行为证据表明， 语音输入到音素的映射，尚未在神经生物学模型中考虑。这 探索性/发展性R21项目追求的核心假设是，听力环境系统地影响 皮质对语音的反应，因此影响信号音素中声学维度的编码。一 一个新成立的跨学科研究小组将使用脑内记录， 立体脑电图（sEEG）在神经外科背景下获得，以追求这一假设。像 皮质电描记术（ECoG）中，sEEG提供高时空分辨率并且可以靶向皮质表面， 包括上级颞回（STG）。由于皮质内电极放置，sEEG电极记录 通过颞上平面，专门针对深沟和回灰质，包括上级 颞沟（STS）和Heschl's回（HG）。同时头皮脑电图（EEG）将 获得这些皮质内的措施与非侵入性的方法适当的研究健康的听众。 目标1将建立对两个声学-语音维度的神经反应作为感知权重的函数， 它们表示音素的同一性。这将为每个参与者提供基线响应，以进行比较， 实验操作听上下文移动感知权重的目标2，并将建立如何个人 知觉加权策略的差异预测皮层电生理反应。目标2将介绍两个 在行为上，相对于基线移动感知权重的成熟操作：引入噪声 以及引入“口音”，对于该口音，短期语音输入偏离了 母语对参与者内部的实验操作进行检查将提供一种敏感的方法， 其用于测定作为在收听期间产生的感知权重的变化的函数的神经响应的变化 contexts.参与者将在青春期后期（15-25岁）进行抽样，在此期间， 权重提供信息异质性。该项目将填补以下方面的一个重要空白， 理解语音处理，建立一个桥梁，从侵入性电生理研究与病人， 通过组合sEEG+EEG测量人类听众的头皮EEG，结合经典和最先进的技术 计算方法，通知机制，并提供一个动态的，灵活的性质的理解， 言语处理与沟通障碍的实质性影响。

ABSTRACT / PROJECT SUMMARY Speech communication plays a crucial role in conveying our thoughts to others, maintaining social ties, and supporting educational achievement. As a result, communication disorders that impact speech perception like autism, dyslexia, and hearing loss can be costly to both individuals and society. Understanding the neurobiological bases of speech processing is an important goal that has been hastened by invasive intracranial electrophysiology in neurosurgical contexts. Yet, substantial behavioral evidence demonstrates dynamic, flexible aspects of the mapping of speech input to phonemes that is not yet accounted for in neurobiological models. This Exploratory/Developmental R21 project pursues the central hypothesis that listening context systematically impacts cortical response to speech and therefore affects the encoding of acoustic dimensions in signaling phonemes. A newly established cross-disciplinary research team will use intracerebral recording via stereoelectroencephalography (sEEG) obtained in a neurosurgical context to pursue this hypothesis. Like electrocorticography (ECoG), sEEG offers high spatiotemporal resolution and can target the cortical surface, including superior temporal gyrus (STG). Owing to the intracortical electrode placement, sEEG electrodes record through the supratemporal plane, specifically targeting both deep sulcal and gyral grey matter including superior temporal sulcus (STS) and Heschl’s gyrus (HG). Simultaneous scalp electroencephalography (EEG) will be acquired to link these intracortical measures with noninvasive approaches appropriate in studies of healthy listeners. Aim 1 will establish neural response to two acoustic-phonetic dimensions as a function of the perceptual weight with which they signal phoneme identity. This will provide a baseline response for each participant for comparison as experimental manipulations to listening context shift perceptual weights in Aim 2, and will establish how individual differences in perceptual weighting strategies predict cortical electrophysiological response. Aim 2 will introduce two well-established manipulations that, behaviorally, shift perceptual weights relative to baseline: introduction of noise and introduction of an ‘accent’ for which the short-term speech input deviates from distributional regularities of the native language. Examination of experimental manipulations within-participant will provide a sensitive means by which to assay changes in neural response as a function of changes in perceptual weights arising across listening contexts. Participants will be sampled across later adolescence (15-25 years), a period during which perceptual weights provide informative heterogeneity. The project will compound its impact by filling an important gap in understanding of speech processing, building a bridge from invasive electrophysiological studies with patients to scalp EEG measures of human listeners through combined sEEG+EEG, wedding classic and state-of-the-art computational approaches to inform mechanisms, and delivering an understanding of the dynamic, flexible nature of speech processing with substantial implications for communication disorders.