NEURAL PROCESSING OF BINAURAL INFORMATION

这项研究计划将评估双耳 信息被分层处理和表示 从地形学上讲，沿着听觉神经轴。 神经处理 双耳信息开始于在上级的会聚 来自两只耳朵的投射橄榄复合体（SOC）， 并且通常认为在这个水平上的双耳交互 建立一个代码，该代码基本上沿着 上行听觉通路到达皮层 然而，分歧 单耳和双耳通路在SOC以外的部位会聚， 从而为潜在的后处理提供结构基底 双耳信息。 这项研究计划将确定 这些更高级别的双耳交互的贡献 通过比较SOC下的反应进行信息处理，劣 丘（IC）和初级听觉皮层（AI）的操作 平均双耳水平和耳间强度差异， 时间 单个神经元在这三个水平的反应， 长爪沙鼠初级听觉通路 将通过细胞外记录和双耳分听进行评估 校准音调和噪声的呈现。 初步数据 表明双耳响应中的几个重要差异， SOC和IC -这个计划将决定在多大程度上， 这些差异代表了涌现的等级过程。 这 对双耳处理的详细评估不仅将阐明 在上行通路中出现了新的编码方案， 但也将允许更详细地检查 双耳响应的地形组织。 比如这 程序将确定人工智能中的总双耳频带是否 根据对以下问题的敏感性， 双耳强度差和平均双耳水平。 最终，这种对多声道处理的检查 听觉系统的水平将产生突触模型， 形成双耳反应的机制。 的最后阶段 在这个五年计划中，将探索这些机制， 直接通过细胞内记录。 知识来自于 这项研究将扩展我们对 双耳信息处理，因此，我们对 单侧和双侧听力损伤的后果。

This research program will evaluate the extent to which binaural information is processed hierarchically and represented topographically along the auditory neuraxis. Neural processing of binaural information begins with convergence at the superior olivary complex (SOC) of projections arising from the two ears, and it is commonly held that binaural interactions at this level establish a code that is relayed essentially unaltered along the ascending auditory pathway to the cortex. However, divergent monaural and binaural pathways converge at sites beyond SOC and thus provide structural substrates for the potential reprocessing of binaural information. This research program will ascertain the contribution of these higher level interactions of binaural information processing by comparing responses at SOC, inferior colliculus (IC) and primary auditory cortex (AI) to manipulation of average binaural level and interaural disparities in intensity and time. The responses of single neurons at these three levels of the primary auditory pathway in the gerbil (Meriones unguiculatus) will be assessed by extracellular recording and dichotic presentation of calibrated tones and noise. Preliminary data indicate several important differences in binaural responses at SOC and IC --- this program will determine the extent to which these differences represent emergent hierarchical processes. This detailed assessment of binaural processing will not only illuminate the emergence of new coding schemes in the ascending pathway, but will also permit examination in greater detail of the topographic organization of binaural responses. For example, this program will determine whether the gross binaural bands in AI mask a more specific organization based on sensitivities to interaural intensity differences and average binaural level. Ultimately, this examination of binaural processing at multiple levels of the auditory system will generate models of the synaptic mechanisms that shape binaural responses. In the final phase of this five year program, these mechanisms will be explored directly by intracellular recording. The knowledge gained from this research will extend our understanding of the principles of binaural information processing and, hence, our appreciation of the consequences of unilateral and bilateral hearing impairment.