Neural Basis of the Perception of Sound Location

在我们的日常生活中，我们会遇到很多声音。 区分它们--识别它们，并确定它们来自哪里--对我们生活的许多方面都是至关重要的从在一个满是人的房间里进行谈话到过马路时避开汽车。在美国国家科学基金会的资助下，杜克大学的詹妮弗·格罗博士和同事们正在研究声音的位置是如何在大脑中表现出来的。 与视觉系统不同，听觉系统似乎不使用地图来编码刺激位置。 相反，新出现的证据表明，至少听觉空间的水平维度是通过神经元群体编码的，这些神经元群体随着声音位于右边或左边的距离而单调增加或减少。 从理论上讲，具有这种反应模式的神经元通过其放电率对声音位置进行编码，这些放电率与特定的声音位置大致一一对应。 然而，这种编码方案的一个关键限制是，同时表示多个声音位置似乎是不可能的，因为神经元不能同时以一个以上的放电速率放电。 然而，人类可以感知多个声音位置。 这是怎么发生的？ 这个项目测试了几个相互竞争的假设，即当存在不止一种声音时，神经元会如何反应。 这些问题的答案将产生重要的新的见解如何声音位置的神经表征辅助听觉感知的这一关键组成部分。 这项研究产生的结果不仅在听觉领域提供了信息，而且还有助于澄清大脑在面对有限的神经资源时可能会更普遍地使用的计算策略。 该项目的资金将用于支持杜克大学的一个研究小组，为认知和计算神经科学的本科生、研究生和博士后学员提供培训机会。

In our daily lives, we are confronted with many sounds. Distinguishing among them--identifying them, and determining where they are coming from--is essential to many aspects of our existence from carrying on a conversation in a room full of people to avoiding cars when crossing the street. With funding from the National Science Foundation, Dr. Jennifer Groh and colleagues at Duke University are investigating how the locations of sounds are represented in the brain. Unlike the visual system, the auditory system does not appear to use maps for encoding stimulus location. Rather, emerging evidence suggests that at least the horizontal dimension of auditory space is encoded via populations of neurons that respond with monotonically increasing or decreasing responses the farther a sound is located to the right or left. In theory, neurons with this kind of response pattern encode sound location via their firing rates, which exhibit a roughly one-to-one correspondence with a particular sound location. A critical limitation of this kind of coding scheme, however, is that the representation of multiple simultaneous sound locations would appear to be impossible because neurons cannot discharge at more than one firing rate at a time. And yet, humans can perceive multiple sound locations. So how does this happen? This project tests several competing hypotheses for how neurons might respond when more than one sound is present. The answers to these questions will yield important new insights into how the neural representation of sound location subserves this critical component of auditory perception. The findings generated by this research will be informative not only in the auditory domain, but will also help clarify the kinds of computational strategies the brain may employ more generally to compress information in the face of limited neural resources. The funding from this project will be used to support a research group at Duke, providing training opportunities for undergraduate, graduate, and post-doctoral trainees in cognitive and computational neuroscience.