Hemispheric asymmetry in auditory processing - spectral and temporal modulations

描述(申请人提供)：语言处理仍然是大脑半球不对称最显著的例子之一。虽然许多研究都集中在阐明功能差异，但偏侧性的确切潜在机制仍不清楚。左侧大脑半球病变的语言功能严重受损，而右侧大脑半球受损则影响韵律的处理。许多在人类和动物模型中的研究都显示出类似的功能不对称，然而，语言半球偏侧化的确切神经机制仍不清楚。已经提出了几个解释功能不对称的假说，包括大脑半球对时间和光谱分辨率的不同能力，信息整合的时间尺度的差异，以及刺激的全局和局部处理。这项研究的目的是 为了提出和检验一个统一的假设，即左半球处理广泛的时间调制和有限范围的光谱调制，而右半球处理广泛的光谱调制和有限范围的时间调制。使用新的刺激滤波技术，我们提出了在频谱调制和时间调制轴上改变语音刺激，并使用脑磁图(MEG)和皮层脑电图术(ECoG)直接验证了我们的假设。具体地说，我们将讨论：1)左右半球对频谱和时间调制的敏感性；2)听觉皮质的任务相关调制；3)更高阶听皮层中的频谱时间听觉感受野。好了！ 与公共卫生相关：追溯到19世纪的临床观察提供了明确的证据，表明左脑而不是右脑的损伤会损害语言处理。虽然有许多关于左右半球在言语、语言和其他认知方面的作用的假说，但大脑半球不对称的确切神经机制仍不清楚。本研究旨在阐明语音左右加工的基本机制，以期加深对语音分析基本机制的理解，丰富语言障碍的诊断和治疗工具。

DESCRIPTION (provided by applicant): Language processing remains one of the most striking examples of hemispheric asymmetry. While much research has focused on elucidating the functional differences, the exact underlying mechanisms of the laterality remain unknown. Language function is severely disrupted in left but not right hemisphere lesions while damage to the right hemisphere impairs the processing of prosody. Many studies in both humans and animal models have exhibited similar functional asymmetries, nevertheless, the exact neuronal mechanisms underlying hemispheric lateralization in language remain unknown. Several hypotheses have been proposed explaining the functional asymmetries, including a differing hemispheric capacity for temporal and spectral resolution, a difference in the temporal scale of information integration as well as global vs. local processing of stimuli. The aim of this study is to propose and test a unifying hypothesis whereby the left hemisphere processes a wide range of temporal modulations and a limited range of spectral modulations and the right hemisphere processes a wide range of spectral modulations and a limited range of temporal modulations. Using novel stimuli filtering techniques, we propose altering speech stimuli on a spectral modulation and temporal modulation axis and directly test our hypothesis using Magnetoencephalography (MEG) and Electrocorticography (ECoG). Specifically, we will address: 1) Left and right hemisphere sensitivity to spectral and temporal modulations; 2) Task-related modulations of auditory cortex; 3) Spectrotemporal auditory receptive fields in higher order auditory cortical fields. ! PUBLIC HEALTH RELEVANCE: Clinical observations dating back to the 19th century provide clear evidence that damage to the left but not right hemisphere impairs language processing. While there exist many hypotheses regarding the roles of the left and right hemispheres in speech, language, and other aspects of cognition, the exact neural mechanisms underlying hemispheric asymmetries remain unknown. The aim of this proposal is to elucidate the mechanisms underlying left and right processing of speech, in a hope to further our understanding of basic mechanisms of speech analysis and enrich the diagnostic and treatment tools for language disorders.