Stebbings Kevin A, Lesicko Alexandria M H, Llano Daniel A
Neuroscience Program, UIUC, USA.
Neuroscience Program, UIUC, USA; Department of Molecular and Integrative Physiology, UIUC, USA; Beckman Institute, Urbana, IL, USA.
Hear Res. 2014 Aug;314:51-9. doi: 10.1016/j.heares.2014.05.004. Epub 2014 Jun 7.
We live in a world imbued with a rich mixture of complex sounds. Successful acoustic communication requires the ability to extract meaning from those sounds, even when degraded. One strategy used by the auditory system is to harness high-level contextual cues to modulate the perception of incoming sounds. An ideal substrate for this process is the massive set of top-down projections emanating from virtually every level of the auditory system. In this review, we provide a molecular and circuit-level description of one of the largest of these pathways: the auditory corticocollicular pathway. While its functional role remains to be fully elucidated, activation of this projection system can rapidly and profoundly change the tuning of neurons in the inferior colliculus. Several specific issues are reviewed. First, we describe the complex heterogeneous anatomical organization of the corticocollicular pathway, with particular emphasis on the topography of the pathway. We also review the laminar origin of the corticocollicular projection and discuss known physiological and morphological differences between subsets of corticocollicular cells. Finally, we discuss recent findings about the molecular micro-organization of the inferior colliculus and how it interfaces with corticocollicular termination patterns. Given the assortment of molecular tools now available to the investigator, it is hoped that his review will help guide future research on the role of this pathway in normal hearing.
我们生活在一个充满各种复杂声音的世界里。成功的听觉交流需要从这些声音中提取意义的能力，即使声音有所衰减。听觉系统采用的一种策略是利用高级上下文线索来调节对传入声音的感知。这一过程的理想基础是从听觉系统几乎每个层面发出的大量自上而下的投射。在这篇综述中，我们对这些通路中最大的一条通路之一：听觉皮质-丘系通路进行分子和回路层面的描述。虽然其功能作用仍有待充分阐明，但该投射系统的激活可迅速而深刻地改变下丘神经元的调谐。我们回顾了几个具体问题。首先，我们描述皮质-丘系通路复杂的异质性解剖结构，特别强调该通路的拓扑结构。我们还回顾了皮质-丘系投射的层状起源，并讨论皮质-丘系细胞亚群之间已知的生理和形态差异。最后，我们讨论了关于下丘分子微组织及其与皮质-丘系终末模式相互作用的最新研究结果。鉴于现在研究人员可获得各种各样的分子工具，希望这篇综述将有助于指导未来关于该通路在正常听力中作用的研究。
