Schmiedt R A, Zwislocki J J
J Acoust Soc Am. 1978 Aug;64(2):502-7. doi: 10.1121/1.382000.
Average tuning curves of single auditory-nerve fibers are compared with average cochlear-microphonic (CM) tuning curves corrected for electrical filtering of the cochlea. Both the neural and CM data were obtained from Mongolian gerbils (Meriones unguiculatus) with the same acoustic system and similar corrections for middle-ear effects. Under these conditions the CM tuning in the second and third cochlear turns is similar to the tuning of fibers whose characteristic frequencies (CFs) correspond to the CM best frequencies (2.5 and 0.5 dHz). Thus, little sharpening seems to take place for low CF fibers. CM tuning at the most apical electrode position is sharper than expected for frequencies below the best frequency--a result that may be due to the shunting effect of the helicotrema at low frequencies- Previous modeling results have confirmed that apical basilar-membrane tuning may be appreciable affected by the mechanical impedance of the helicotrema. This helicotrema effect may account for the nearly symmetrical shapes of neural tuning curves of low-CF fibers.
将单根听神经纤维的平均调谐曲线与经耳蜗电滤波校正后的平均耳蜗微音电位（CM）调谐曲线进行比较。神经数据和CM数据均取自蒙古沙鼠（长爪沙鼠），使用相同的声学系统，并对中耳效应进行了类似的校正。在这些条件下，耳蜗第二和第三转的CM调谐与特征频率（CF）对应于CM最佳频率（2.5和0.5 dHz）的纤维的调谐相似。因此，低CF纤维似乎几乎没有锐化现象。在最顶端电极位置，低于最佳频率的频率的CM调谐比预期的更尖锐——这一结果可能是由于低频时蜗孔的分流效应所致。先前的建模结果证实，蜗孔的机械阻抗可能会显著影响顶端基底膜的调谐。这种蜗孔效应可能解释了低CF纤维神经调谐曲线几乎对称的形状。
