NONLINEAR INPUT-OUTPUT FUNCTIONS DERIVED FROM THE RESPONSES OF GUINEA-PIG COCHLEAR NERVE-FIBERS - VARIATIONS WITH CHARACTERISTIC FREQUENCY
NONLINEAR INPUT-OUTPUT FUNCTIONS DERIVED FROM THE RESPONSES OF GUINEA-PIG COCHLEAR NERVE-FIBERS - VARIATIONS WITH CHARACTERISTIC FREQUENCY
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DOI：
10.1016/0378-5955(94)90028-0
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发表时间：
1994-08-01
期刊：
影响因子：
2.8
通讯作者：
YATES, GK
中科院分区：
文献类型：
--
作者：
COOPER, NP;YATES, GK
记录麻醉豚鼠耳蜗神经纤维的频率-水平函数（RLF）。这些函数的形状随频率的变化被用来推导耳蜗中机械预处理机制的输入-输出（IO）关系。假设这些预处理机制在远低于每个纤维的特征频率（CF）的频率下线性地操作。在每个纤维的CF导出的IO功能提供了强有力的证据，压缩非线性预处理在大多数地区的耳蜗。然而，压缩的明显程度取决于纤维的CF，因此对耳蜗神经支配的推定网站。对于CF在1.5和3.6 kHz之间的纤维，CF导出的10个函数以约0.5 dB/dB的速率增长。对于CF高于4 kHz的纤维，IO功能更具压缩性，高强度渐近斜率约为0.13 dB/dB。在最高（大于或等于10 kHz）的CF纤维，压缩的程度取决于耳蜗的生理条件;推导出的IO功能变得更加线性的耳蜗变得不那么敏感。衍生的IO技术不太适合分析由非常低的频率（例如，< 500 Hz）音调。尽管如此，CF低于类似于1 KHz的纤维的CF RLF提供了耳蜗顶点附近的机械非线性的证据很少。这些发现意味着耳蜗预处理机制的纵向变化，并为耳蜗功能模型提供了重要的新测试。
Rate-versus-level functions (RLFs) were recorded from individual cochlear nerve fibres in anaesthetised guinea-pigs. Variations in the shapes of these functions with frequency were used to derive input-output (IO) relationships for the mechanical preprocessing mechanisms in the cochlea. It was assumed that these preprocessing mechanisms operated linearly at frequencies well below each fibre's characteristic frequency (CF). The IO functions derived at each fibre's CF provided strong evidence of compressively nonlinear preprocessing in most regions of the cochlea. However, the apparent degree of compression depended on the fibre's CF, and hence on the presumed site of cochlear innervation. For fibres with CFs of between 1.5 and 3.6 kHz, the CF derived 10 functions grew at rates of around 0.5 dB/dB. For fibres with CFs above 4 kHz, the IO functions were more compressive, with high-intensity asymptotic slopes of around 0.13 dB/dB. In the highest (greater than or equal to 10 kHz) CF fibres, the degree of compression depended on the physiological condition of the cochlea; the derived IO functions becoming more linear as the cochlea became less sensitive. The derived IO technique was not well suited to analyse responses evoked by very low frequency (e.g., < 500 Hz) tones. Nonetheless, the CF RLFs from fibres with CFs lower than similar to 1 KHz provided little evidence of mechanical nonlinearity near the apex of the cochlea. These findings imply a longitudinal variation in the mechanisms of cochlear preprocessing, and provide important new tests for functional models of the cochlea.