Neural predictors of individual differences in speech perception

言语感知将声音映射为意义。在发展过程中，对意义重要的声音差异比那些不重要的声音差异在感知上变得更加突出。令人惊讶的是，成年人在感知属于同一语音类别的不同声音的能力方面表现出很大的差异。尽管有相当多的证据证明了这种差异性，但关于神经生物学和言语知觉行为的研究很少考虑这种知觉多样性。这个项目将解决这些问题。在一组不同的年轻人中，将研究涉及言语感知的大脑系统，从脑干到皮质。具体地说，这个项目将测试神经编码的变化预测语音感知和理解的个体差异的理论。这些研究可能会为嘈杂环境中的听力或致残障碍的治疗提供新的解决方案。通过公众宣传，该项目将促进言语感知的神经科学，并培养人们对言语感知在教育和劳动力中的重要性的认识。语音感知将一组复杂的声音映射到有限数量的语音类别。范畴知觉使听者能够应对语音中的声学变化，通过提高对类别边界上的声学差异的敏感度，并降低类别内的敏感度。个体在“范畴”上表现出相当大的差异，“范畴”指的是对语音类别内的声学变化的敏感程度。尽管有相当多的证据表明个体在类别上的差异，但关于个体差异如何与神经处理流或其他言语和语言的行为测量相关的信息却知之甚少。目前的项目测试了这一假设，即言语感知中的ID来自从脑干到皮质的神经处理流中的ID。该项目研究了年轻人(n=100)在听觉通路早期水平(使用听觉脑干反应(ABR)测量)和皮质水平(使用功能磁共振测量)的神经处理。这些任务包括对可能导致声音和语音表现的个体差异的因素的行为测量，例如音乐技能和阅读能力的测量。ABR、fMRI和Behavior的结合将把语音处理中的ID与脑干中声音编码的神经精确度和大脑皮质中语音反应的神经特异性联系起来。它还将阐明感知和神经编码方面的身份识别如何在完善的言语和语言度量中解释身份识别。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Speech perception maps sounds into meaning. During development, sound differences important to meaning become more perceptually salient than those that are unimportant. Surprisingly, adults show wide variability in the ability to perceive differences between sounds that belong to the same speech category. Despite considerable evidence for this variability, studies of the neurobiology and behavior of speech perception rarely take this perceptual diversity into account. This project will tackle these questions. In a diverse group of young adults, the brain systems involved in speech perception will be studied, from the brainstem to the cortex. Specifically, this project will test the theory that variation in neural encoding predict individual differences in speech perception and comprehension. These studies may indicate novel solutions for hearing in noisy environments or for treatments for disabling disorders. Through public outreach, this project will promote the neuroscience of speech perception, and foster awareness of the importance of speech perception in education and for the workforce. Speech perception maps a complex set of sounds to a limited number of phonetic categories. Categorical perception enables the listener to cope with acoustic variability in speech, by heightening sensitivity to acoustic differences across category boundaries, and lessening sensitivity within categories. Individuals show sizeable differences in “categoricity,” the degree of sensitivity to acoustic variability within a speech sound category. Despite considerable evidence of individual differences (IDs) in categoricity, little is known of how IDs relate to the neural processing stream or to other behavioral measures of speech and language. The current project tests the hypothesis that IDs in speech perception arise from IDs in the neural processing stream, from brainstem to cortex. The project studies the neural processing of younger adults (n=100) at early levels of the auditory pathway, measured using the auditory brainstem response (ABR); and at cortical levels, measured using fMRI. The tasks include behavioral measures of factors that may drive individual differences in sound and speech representation, such as musical skill and measures of reading ability. The combination of ABR, fMRI, and behavior will link IDs in speech processing to neural precision in sound encoding in the brainstem and neural specificity for phonetic responses in cortex. It will also elucidate how IDs in perception and neural encoding explain IDs in well-established speech and language metrics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.