Effects of interaural time delays of noise stimuli on low-frequency cells in the cat's inferior colliculus. II. Responses to band-pass filtered noises.
Effects of interaural time delays of noise stimuli on low-frequency cells in the cat's inferior colliculus. II. Responses to band-pass filtered noises.
复制标题
噪声刺激的耳间时间延迟对猫下丘低频细胞的影响。
DOI：
10.1152/jn.1987.58.3.543
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发表时间：
1987
影响因子：
2.5
通讯作者：
Musicant,AD
中科院分区：
文献类型：
--
作者：
Chan,JC;Yin,TC;Musicant,AD
1.我们研究了猫下丘中央核的细胞，这些细胞对耳间时间延迟（ITDs）敏感，以评估噪声信号的刺激谱的影响。刺激是急剧过滤的低，高，带通噪声信号，其截止频率和带宽系统地变化。对这些噪声信号的ITD的响应与对宽带噪声和纯音的ITD获得的响应进行了比较。2.作为ITD的函数的响应于带通噪声的放电率通常是具有在较长ITD处减小的峰值幅度的循环函数。相邻峰之间的平均间隔的倒数表示响应速率随ITD变化的速度，称为响应频率（RF）。该RF近似等于由细胞的同步速率曲线过滤的刺激频谱的中值频率，该曲线是耳间相位的同步和放电速率相对于频率绘制的产物。这表明，RF是由刺激中的所有频谱分量决定的，这些频谱分量落在细胞反应同步的频率范围内。每个分量的贡献与该频率的同步速率成比例。3. ITD功能的中心峰值通常落在ITD的生理范围内（+/-400微秒）。与对不同频率的音调的反应相比，该峰的位置并不随刺激频谱的变化而显著变化。它的形状也保持不变，除了宽度减少时，在同步率曲线的范围内的高频成分被添加到刺激。少数细胞以最小放电而不是最大接近零的ITD响应，并且该中心最小值具有与中心峰值相似的性质。ITD函数的次峰的幅度随着与同步率曲线重叠的刺激带宽的加宽而减小。4.两个带通信号的ITD函数之和类似于其频谱由带通频谱之和组成的宽带信号的ITD函数之和。5.从这些双耳响应中，我们可以推断双耳神经元的单耳输入的响应特征。然后，我们通过研究低频梯形体纤维对带通噪声的响应来验证这些预测。
1. We studied cells in the central nucleus of the inferior colliculus of the cat that were sensitive to interaural time delays (ITDs) in order to evaluate the influence of the stimulus spectrum of noise signals. Stimuli were sharply filtered low-, high-, and band-pass noise signals whose cutoff frequencies and bandwidths were systematically varied. The responses to ITDs of these noise signals were compared with responses obtained to ITDs of broadband noise and pure tones. 2. The discharge rate in response to band-pass noise as a function of ITD was usually a cyclic function with decreasing peak amplitudes at longer ITDs. The reciprocal of the mean interval between adjacent peaks indicated how rapidly the response rate varied with ITD and was termed the response frequency (RF). This RF was approximately equal to the median frequency of the stimulus spectrum filtered by the cell's sync-rate curve, which was the product of the synchronization to interaural phase and the discharge rate plotted against frequency. This suggests that the RF was determined by all the spectral components in the stimulus that fell within the frequency range in which the cell's response was synchronized. The contribution of each component was proportional to the sync-rate for that frequency. 3. The central peak of the ITD function usually fell within the physiological range of ITDs (+/- 400 microseconds). The location of this peak did not vary significantly with changes in stimulus spectrum by comparison with responses to tones of different frequency. Its shape also remained constant, except for a decrease in width when high-frequency components within the range of the sync-rate curve were added to the stimulus. A few cells responded with a minimal discharge instead of a maximal near-zero ITD, and this central minimum had similar properties as the central peak. The amplitude of the secondary peaks of the ITD function decreased as the stimulus bandwidth that overlapped the sync-rate curve broadened. 4. The sum of the ITD functions to two band-pass signals was similar to that of a broadband signal whose spectrum was composed of the sum of the band-pass spectra. 5. From these binaural responses we could make inferences about the response characteristics of the monaural inputs to binaural neurons. We then verified these predictions by studying responses of low-frequency trapezoid body fibers to band-pass noises.