Neural encoding of sound source location in the presence of a concurrent, spatially separated source
Neural encoding of sound source location in the presence of a concurrent, spatially separated source
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DOI：
10.1152/jn.00303.2012
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发表时间：
2012-11-01
影响因子：
2.5
通讯作者：
Delgutte, Bertrand
中科院分区：
文献类型：
--
作者：
Day, Mitchell L.;Koka, Kanthaiah;Delgutte, Bertrand
第ML天，科卡K，Delgutte B。同时存在空间分离声源时声源定位的神经编码。J Neurophysiol 108：2612-2628，2012.首次发表于2012年8月22日; doi：10.1152/jn.00303.2012.-在存在多个空间上分离的声源的情况下，用于水平面中的声音定位的双耳线索从来自孤立的每个声音的线索变得失真，然而在日常多频声学环境中的定位仍然是鲁棒的。我们研究了未麻醉兔下丘（IC）神经元的方位角调谐功能的变化，以一个目标宽带噪声时，同时宽带噪声发生器在虚拟声学空间的不同位置。存在的干扰一般降低敏感性目标方位角和扭曲的形状的调谐功能，但大多数神经元仍然显着敏感的目标方位角，并保持调谐功能的形状有点类似于那些单独的目标。在虚拟声学空间中使用双耳线索操作，我们发现具有高最佳频率（BF）的神经元的单源调谐功能主要由耳间水平差（ILD）或单耳水平决定，在某些神经元中耳间时间差（ITDs）的影响很小。然而，与一个位于中央的神经元，大多数高BF神经元的调谐功能的强烈影响ITDs以及ILD。基于模型的分析表明，这些调谐函数的形状部分是由与源分离一起发生的左右耳蜗诱导的包络的去相关产生的。ITD对高BF神经元的调谐功能的强烈影响对声音定位的“双工理论”提出了挑战，并表明ITD可能对定位多频环境中的高频声音很重要。
Day ML, Koka K, Delgutte B. Neural encoding of sound source location in the presence of a concurrent, spatially separated source. J Neurophysiol 108: 2612-2628, 2012. First published August 22, 2012; doi:10.1152/jn.00303.2012.-In the presence of multiple, spatially separated sound sources, the binaural cues used for sound localization in the horizontal plane become distorted from the cues from each sound in isolation, yet localization in everyday multisource acoustic environments remains robust. We examined changes in the azimuth tuning functions of inferior colliculus (IC) neurons in un-anesthetized rabbits to a target broadband noise when a concurrent broadband noise interferer was presented at different locations in virtual acoustic space. The presence of an interferer generally degraded sensitivity to target azimuth and distorted the shape of the tuning function, yet most neurons remained significantly sensitive to target azimuth and maintained tuning function shapes somewhat similar to those for the target alone. Using binaural cue manipulations in virtual acoustic space, we found that single-source tuning functions of neurons with high best frequencies (BFs) were primarily determined by interaural level differences (ILDs) or monaural level, with a small influence of interaural time differences (ITDs) in some neurons. However, with a centrally located interferer, the tuning functions of most high-BF neurons were strongly influenced by ITDs as well as ILDs. Model-based analysis showed that the shapes of these tuning functions were in part produced by decorrelation of the left and right cochlea-induced envelopes that occurs with source separation. The strong influence of ITD on the tuning functions of high-BF neurons poses a challenge to the "duplex theory" of sound localization and suggests that ITD may be important for localizing high-frequency sounds in multisource environments.