Visual Responses in the Inferior Colliculus

描述（由申请人提供）：感知本质上是多感官的。动物并不生活在独立的听觉和视觉世界中，它们体验到丰富的环境，并与各种感官相结合的线索进行互动。视听处理能力的受损直接影响人类健康，因为成功的组合对于理解语音、定位环境中的重要事件和引导注意力至关重要。近年来，几个单一感觉区域被证明对另一种感觉有反应。因此，如果没有对非听觉影响的彻底调查，对传统定义的听觉通路的理解似乎是不完整的。最近的工作（波特等人，PNAS，2007）已经证明了灵长类下丘（IC）的神经元中的明显视觉反应。IC是一个皮质下结构，几乎所有的听觉信息都会通过它，所以视觉的影响很可能对听觉处理有很大的影响。这是听觉通路中最早发现视觉影响的一点。在IC中视觉反应对听觉处理有什么影响？这个建议旨在阐明视觉和听觉刺激的神经反应如何在灵长类IC中相互作用。具体地，本文所述的实验旨在（1）研究IC内视觉响应的分布，（2）研究视觉响应的空间和（3）时间敏感性，并与听觉响应直接比较。在第三个目标的时间属性的灵长类动物IC的感官整合的基础上，将探讨依赖于刺激的内容，通过观察同种发声，其中有一个自然的听觉和视觉组件之间的时间偏移的反应。所有描述的实验都将使用来自警觉猴子的细胞外记录，详细分析单个神经元的活动以及局部场电位的缓慢变化。 公共卫生相关性：下丘是一个听觉脑核团，由于其手术可及性及其在听觉通路内的位置，最近已成为假体装置的候选区域。了解IC如何整合灵长类动物的视觉反应是为听觉神经受损的患者创造可用的假体植入物的关键一步。这项建议将揭示重要的信息，以指导这些植入物的设计，以及对视听整合的更普遍的理解，这关系到各种各样的疾病。

DESCRIPTION (provided by applicant): Perception is inherently multisensory. Animals do not live in separate auditory and visual worlds, they experience a rich environment and interact with cues that are combined across the senses. Impairment of audiovisual processing abilities directly impacts human health, as successful combination is crucial for understanding speech, localizing important events in the environment, and guiding attention. In recent years, several putatively unisensory areas have been shown to respond to an alternate sense. Thus, it seems that an understanding of the traditionally defined auditory pathway is not complete without a thorough investigation of non-auditory influences. Recent work (Porter et al., PNAS, 2007) has demonstrated overt visual responses in neurons of the primate inferior colliculus (IC). The IC is a subcortical structure that nearly all ascending auditory information passes through, so visual influences here likely have a large impact on auditory processing. This is the earliest point in the auditory pathway that visual influences have ever been found. What effect do visual responses have on auditory processing in IC? This proposal seeks to shed light on how neural responses to visual and auditory stimuli interact in the primate IC. Specifically, the experiments described herein aim to (1) investigate the distribution of visual responses within the IC, (2) investigate the spatial and (3) temporal sensitivity of visual responses, with a direct comparison to auditory responses. In the third aim temporal properties underlying integration of the senses in the primate IC will be probed for dependence on the content of the stimulus by looking at responses to conspecific vocalizations, which have a natural temporal offset between their auditory and visual components. All of the experiments described will use extracellular recordings from alert monkeys, with a detailed analysis of the activity of single neurons as well as slower changes in the local field potential. PUBLIC HEALTH RELEVANCE: The inferior colliculus is an auditory brain nucleus that has recently emerged as a candidate region for prosthetic devices, due to its surgical accessibility and its location within the auditory pathway. Understanding how the IC integrates visual responses in primates is a critical step in creating a usable prosthetic implant for patients who have damage to the auditory nerve. This proposal will uncover important information to guide the design of these implants, as well as a more general understanding of audiovisual integration which bears on a wide variety of disorders.