Neurophysiology of robust speech perception in human superior temporal gyrus

描述(申请人提供)：对于听力正常的听者来说，在拥挤、嘈杂的环境中感知和跟随说话人是一项常见的任务。然而，潜在的神经生理学是复杂的，对于患有外周和中枢听觉通路障碍的人来说，这项任务仍然是一项斗争。缺乏一个详细的神经生物学模型来解释强健的言语感知的机制和功能，这阻碍了我们对这些过程如何在痛苦的人群中受到损害的理解。在我们的创新方法中，我们将记录高密度微电极和宏电极阵列，通过手术植入癫痫患者的颞上回，作为他们临床评估的一部分。这种方法提供了一个关于大脑皮层种群活动的异常详细的视角。我们将基于最近的两个互补发现，其中我们确定了语音特征的高度选择性、空间分布的神经表示(Mesgarani et。艾尔科学，2014)，它同时是高度动态的，可以迅速变化，以反映听者的感知偏见(Mesgarani&Chang，自然，2012)。虽然这些研究意义重大，但它们揭示了我们对这一进程理解上的一些差距，我们打算在本提案中加以解决。具体地说，我们将解决以下悬而未决的问题：1)语音和说话人特征的联合编码的神经机制是什么？2)注意如何调节神经反应的语音和说话人特征的选择性？(3)什么计算机制可以解释STG反应的动态特征选择性？回答这些问题将极大地促进我们对人类非凡能力的理解，并将引起包括神经学家、感觉和认知神经学家在内的许多领域的研究人员的极大兴趣。

DESCRIPTION (provided by applicant): Perceiving and following an individual speaker in a crowded, noisy environment is a commonplace task for listeners with normal hearing. The underlying neurophysiology, however, is complex, and the task remains a struggle for people with peripheral and central auditory pathway disorders. The lack of a detailed neurobiological model of mechanisms and functions underlying robust speech perception has hindered our understanding of how these processes become impaired in the suffering population. In our innovative approach, we will record from high-density micro and macro electrode arrays surgically implanted on the superior temporal gyrus of epilepsy patients as part of their clinical evaluation. This method offers an exceptionally detailed perspective of cortical population activity. We will build upon two recent complementary findings where we identified a highly selective, spatially distributed neural representation of phonetic features (Mesgarani et. al. Science, 2014), which at the same time is highly dynamic and can change rapidly to reflect the perceptual bias of the listener (Mesgarani & Chang, Nature 2012). While significant, these studies revealed several gaps in our understanding of this process, which we intend to address in this proposal. Specifically, we will resolve the following unanswered questions: 1) what is the neural mechanism for joint encoding of both phonetic and speaker features? 2) How does attention modulate phonetic and speaker feature selectivity of neural responses? And 3) what computational mechanisms can account for dynamic feature selectivity of responses in STG? Answering these questions will significantly advance our understanding of a remarkable human ability, and will be of great interest to researchers from many areas including neurologists, and sensory and cognitive neuroscientists.