头部无约束猫二维优先效应的行为与建模
Behavior and modeling of two-dimensional precedence effect in head-unrestrained cats.
作者信息
Gai Yan, Ruhland Janet L, Yin Tom C T
机构信息
Department of Neuroscience, University of Wisconsin, Madison, Wisconsin; and Department of Biomedical Engineering, Saint Louis University, St. Louis, Missouri
Department of Neuroscience, University of Wisconsin, Madison, Wisconsin; and.
出版信息
J Neurophysiol. 2015 Aug;114(2):1272-85. doi: 10.1152/jn.00214.2015. Epub 2015 Jul 1.
The precedence effect (PE) is an auditory illusion that occurs when listeners localize nearly coincident and similar sounds from different spatial locations, such as a direct sound and its echo. It has mostly been studied in humans and animals with immobile heads in the horizontal plane; speaker pairs were often symmetrically located in the frontal hemifield. The present study examined the PE in head-unrestrained cats for a variety of paired-sound conditions along the horizontal, vertical, and diagonal axes. Cats were trained with operant conditioning to direct their gaze to the perceived sound location. Stereotypical PE-like behaviors were observed for speaker pairs placed in azimuth or diagonally in the frontal hemifield as the interstimulus delay was varied. For speaker pairs in the median sagittal plane, no clear PE-like behavior occurred. Interestingly, when speakers were placed diagonally in front of the cat, certain PE-like behavior emerged along the vertical dimension. However, PE-like behavior was not observed when both speakers were located in the left hemifield. A Hodgkin-Huxley model was used to simulate responses of neurons in the medial superior olive (MSO) to sound pairs in azimuth. The novel simulation incorporated a low-threshold potassium current and frequency mismatches to generate internal delays. The model exhibited distinct PE-like behavior, such as summing localization and localization dominance. The simulation indicated that certain encoding of the PE could have occurred before information reaches the inferior colliculus, and MSO neurons with binaural inputs having mismatched characteristic frequencies may play an important role.
优先效应(PE)是一种听觉错觉,当听众定位来自不同空间位置的几乎同时且相似的声音时会出现,例如直达声及其回声。它主要在头部静止的人类和动物的水平面中进行研究;扬声器对通常对称地位于额半视野中。本研究在头部不受限制的猫中,沿着水平、垂直和对角线轴,针对各种配对声音条件检查了优先效应。通过操作性条件反射训练猫将目光转向感知到的声音位置。当刺激间隔时间变化时,观察到放置在方位角或额半视野对角线上的扬声器对出现了典型的类似优先效应的行为。对于位于正中矢状面的扬声器对,未出现明显的类似优先效应的行为。有趣的是,当扬声器对角放置在猫前方时,沿着垂直维度出现了某些类似优先效应的行为。然而,当两个扬声器都位于左半视野时,未观察到类似优先效应的行为。使用霍奇金 - 赫胥黎模型来模拟内侧上橄榄核(MSO)中的神经元对方位角声音对的反应。新颖的模拟纳入了低阈值钾电流和频率失配以产生内部延迟。该模型表现出明显的类似优先效应的行为,如总和定位和定位优势。模拟表明,在信息到达下丘之前可能已经发生了优先效应的某些编码,并且具有双耳输入且特征频率不匹配的MSO神经元可能起重要作用。