Ear Institute, University College London, London, UK.
Adv Exp Med Biol. 2013;787:39-46. doi: 10.1007/978-1-4614-1590-9_5.
It is possible that previous psychophysical estimates of basilar membrane gain and compression using temporal masking curve (TMC) and additivity of forward masking (AFM) methods using long-duration maskers (>30 ms) could have been affected by activation of the medial olivocochlear reflex (MOCR) (Jennings et al. ; Plack and Arifianto ). In experiment 1, AFM and TMC methods were compared to a new fixed-duration masking curve (FDMC) method in which the combined masker and signal stimulus duration is fixed at 25 ms. Estimates of compression were found to be not significantly different for TMC, FDMC and AFM methods. Estimates of gain were similar for TMC and FDMC methods. Maximum compression was associated with a significantly lower input masker level using the FDMC compared to the TMC method. In experiment 2, the FDMC method was used to investigate the effect of efferent activation on gain and compression estimates by presenting a precursor sound prior to the combined masker-signal stimulus. Estimated gain decreased as precursor level increased, and increased as the silent interval between the precursor and combined masker-signal stimulus increased, consistent with a decay of the efferent response.
使用时间掩蔽曲线（TMC）和使用长时掩蔽器（>30ms）的前向掩蔽（AFM）方法对基底膜增益和压缩的先前心理物理估计，可能受到内侧橄榄耳蜗反射（MOCR）的激活的影响（Jennings 等人；Plack 和 Arifianto）。在实验 1 中，将 AFM 和 TMC 方法与一种新的固定时长掩蔽曲线（FDMC）方法进行了比较，其中组合掩蔽器和信号刺激的持续时间固定为 25ms。发现 TMC、FDMC 和 AFM 方法的压缩估计值没有显著差异。TMC 和 FDMC 方法的增益估计值相似。与 TMC 方法相比，FDMC 方法中使用固定时长掩蔽曲线时，最大压缩与显著较低的输入掩蔽器水平相关。在实验 2 中，使用 FDMC 方法通过在组合掩蔽器-信号刺激之前呈现前导声来研究传出激活对增益和压缩估计的影响。随着前导水平的增加，估计的增益减小，随着前导和组合掩蔽器-信号刺激之间的无声间隔增加，增益增加，这与传出反应的衰减一致。
