The Neural Bases of Statistical and Referential Cues to Phonetic Category Structu

描述(申请人提供)：这项研究的目的是调查成年人习得新语音类别能力的神经机制。具体地说，我们将调查输入的统计和参照属性的经验如何沿着声学-语音连续体塑造受试者对项目的知觉敏感性，以及这些敏感性变化的神经关联。这将通过使用功能磁共振成像(FMRI)来测量成年受试者的激活模式，这些受试者已经熟悉了来自非母语语音连续体的听觉刺激。重要的是，在熟悉过程中呈现的听觉刺激的统计分布以及伴随听觉刺激的视觉/参照线索将是不同的，以便分离统计线索和参照线索与语音类别同一性的神经关联。我们将使用短间隔习惯化范式来探讨神经结构对连续体不同位置等效声间隔的敏感性，在该范式中，FMR信号的适应释放被用作神经对语音范畴结构变化的敏感性的标志。有人认为，激活作为熟悉度的函数在后上回等区域的变化表明，语音范畴结构的变化在语音加工流中起着早期的调节作用。或者，额叶(额叶下回)和顶叶(缘上回、角回)结构的激活变化可能表明语音类别的扭曲发生在加工流程的较晚阶段，反映了注意、词汇或执行系统的招募。结果将阐明统计和参照线索形成知觉敏感性的过程，而知觉敏感性最终形成语音类别的基础。 相关性：这项拟议的研究将阐明语音类别习得背后的神经机制，并最终可能被用来指导患有发育性语言障碍的儿童的治疗策略。此外，这一结果将有助于我们对成人语言处理的神经基础的理解，这可能被用来为因脑损伤而遭受语言障碍的失语症患者提供康复策略。

DESCRIPTION (provided by applicant): The goal of this research is to investigate the neural mechanisms which underlie adults' ability to acquire new phonetic categories. Specifically, we will investigate how experience with statistical and referential properties of the input shapes subjects' perceptual sensitivities to items along an acoustic-phonetic continuum, and the neural correlates of these changes in sensitivity. This will be accomplished by using functional MRI (fMRI) to measure activation patterns in adult subjects who have been familiarized with auditory stimuli taken from a non-native phonetic continuum. Importantly, the statistical distribution of the auditory stimuli presented during familiarization, as well as the visual/referential cues which accompany the auditory stimuli will be varied in order to isolate neural correlates of statistical and referential cues to phonetic category identity. Sensitivity of neural structures to equivalent acoustic intervals at different locations along the continuum will be probed using a short-interval habituation paradigm, in which release from adaptation of the fMR signal is used as a marker for neural sensitivity to changes in phonetic category structure. It is argued that changes in activation as a function of familiarization in such areas as the posterior superior temporal gyrus would suggest that the changes in phonetic category structure are mediated early in the phonetic processing stream. Alternatively, changes in activation in the frontal (inferior frontal gyrus) and parietal (supramarginal gyrus, angular gyrus) structures would suggest that the warping of phonetic categories occurs later in the processing stream and reflects the recruitment of attentional, lexical, or executive systems. Results will shed light on the process by which statistical and referential cues shape perceptual sensitivities which ultimately form the basis of phonetic categories. Relevance: The proposed research will shed light on the neural mechanisms which underlie the acquisition of phonetic categories, and may ultimately be used to inform treatment strategies for children with developmental language disorders. Additionally, results should add to our understanding of the neural bases of speech processing in adults, which may be used to suggest rehabilitative strategies for aphasic patients who have suffered language impairments due brain injury.