AUDITORY NEURAL CODING OF SPEECH

描述：(改编自《调查者摘要》)大部分演讲 对话发生在存在相互竞争的声音的情况下，例如其他声音或 环境噪音。听力受损的人经常抱怨有困难 即使他们在安静的环境下也能很好地理解噪音背景下的讲话。而当 声调直接掩蔽的生理机制 外周听觉系统是很好理解的，但情况并非如此 涉及空间、时间和交叉频率的复杂形式的掩蔽 很可能是中心起源的相互作用，可能会降低语言质量 在有竞争声音的情况下接受。我们建议调查 言语掩蔽的外周和中枢神经机制 其他声刺激，通过测量单个单元的掩蔽阈值 听神经(AN)和下丘(IC)使用相同刺激和 如心理物理实验中的检测措施。 具体目标1是测试陷波噪声的生理有效性 心理物理学家用来从掩蔽中估计听觉滤过器形状的方法 人类的数据。 目标2是研究前向掩蔽的神经基础，它是最小的 在AN-BUT中，在IC中可以与心理物理前向掩蔽相媲美。 目标3是找到从掩饰中释放出来的神经关联 当以相同频率调幅的附加声音 介绍了MASKER的基本原理。这种“共调掩蔽释放”被认为有助于 在存在共享共同的干扰声音的情况下的语音接收 宽频率范围内的调制模式。 目标4是确定对简单刺激的神经掩蔽措施是否可以 被用来预测语音中特定语音对比的掩蔽。这 研究涉及听觉理论中的基本问题，如神经 听觉分组的机制、外周因素和中枢因素在脑损伤中的作用 掩蔽，以及用于信号检测的神经代码。这可能会导致 更好地理解为什么听力受损和老年听众有更多 在相互竞争的声音之间理解语音比正常情况下更难 听者，并可能有助于开发新型助听器和听觉 (耳蜗和脑干)在嘈杂环境中表现更好的植入物。

DESCRIPTION: (Adapted from the Investigator's Abstract) Most speech conversations occur in the presence of competing sounds such as other voices or environmental noise. Hearing-impaired people often complain of difficulties understanding speech in noise backgrounds even if they do well in quiet. While physiological mechanisms underlying the direct masking of tones in the peripheral auditory system are well understood, this is not the case for more complex forms of masking involving spatial, temporal and cross-frequency interactions that are likely to be of central origin, and may degrade speech reception in the presence of competing sounds. We propose to investigate peripheral and central neural mechanisms underlying the masking of speech and other acoustic stimuli by measuring masked thresholds of single units in the auditory-nerve (AN) and inferior colliculus (IC) using the same stimuli and detection measures as in psychophysical experiments. Specific Aim 1 is to test the physiological validity of the notched-noise method used by psychophysicists to estimate auditory filter shapes from masking data in humans. Aim 2 is to investigate the neural basis for forward masking, which is minimal in the AN but, in the IC may be comparable to psychophysical forward masking. Aim 3 is to find neural correlates of the release from masking which occurs when additional sounds that are amplitude-modulated at the same frequency as a masker are introduced. Such "comodulation masking release" is thought to aid speech reception in the presence of interfering sounds that share a common pattern of modulation over broad frequency ranges. Aim 4 is to determine whether measures of neural masking for simple stimuli can be used to predict the masking of specific phonetic contrasts in speech. This research addresses fundamental issues in auditory theory such as neural mechanisms of auditory grouping, the roles of peripheral and central factors in masking, and the neural codes used for signal detection. It may lead to a better understanding of why hearing-impaired and elderly listeners have greater difficulties understanding speech among competing sounds than do normal listeners, and may help develop new kinds of hearing aids and auditory (cochlear and brainstem) implants that perform better in noisy environments.