Bonham B H, Lewis E R
Department of Otolaryngology, University of California, San Francisco 94143-0732, USA.
J Acoust Soc Am. 1999 Jul;106(1):281-90. doi: 10.1121/1.427056.
A commonly accepted physiological model for lateralization of low-frequency sounds by interaural time delay (ITD) stipulates that binaural comparison neurons receive input from frequency-matched channels from each ear. Here, the effects of hypothetical interaural frequency mismatches on this model are reported. For this study, the cat's auditory system peripheral to the binaural comparison neurons was represented by a neurophysiologically derived model, and binaural comparison neurons were represented by cross-correlators. The results of the study indicate that, for binaural comparison neurons receiving input from one cochlear channel from each ear, interaural CF mismatches may serve to either augment or diminish the effective difference in ipsilateral and contralateral axonal time delays from the periphery to the binaural comparison neuron. The magnitude of this increase or decrease in the effective time delay difference can be up to 400 microseconds for CF mismatches of 0.2 octaves or less for binaural neurons with CFs between 250 Hz and 2.5 kHz. For binaural comparison neurons with nominal CFs near 500 Hz, the 25-microsecond effective time delay difference caused by a 0.012-octave CF mismatch is equal to the ITD previously shown to be behaviorally sufficient for the cat to lateralize a low-frequency sound source.
一种被广泛接受的通过双耳时间延迟（ITD）实现低频声音侧向化的生理模型规定，双耳比较神经元从每只耳朵的频率匹配通道接收输入。在此，报告了假设的双耳频率失配对该模型的影响。在本研究中，双耳比较神经元外周的猫听觉系统由一个神经生理学推导模型表示，双耳比较神经元由互相关器表示。研究结果表明，对于从每只耳朵的一个耳蜗通道接收输入的双耳比较神经元，双耳CF失配可能会增强或减弱从外周到双耳比较神经元的同侧和对侧轴突时间延迟的有效差异。对于CF在250 Hz至2.5 kHz之间的双耳神经元，当CF失配为0.2倍频程或更小时，有效时间延迟差异的增加或减少幅度可达400微秒。对于标称CF接近500 Hz的双耳比较神经元，由0.012倍频程CF失配引起的25微秒有效时间延迟差异等于先前显示的在行为上足以使猫对低频声源进行侧向化的ITD。
