INTENSITY DISCRIMINATION IN FORWARD MASKING
INTENSITY DISCRIMINATION IN FORWARD MASKING
复制标题
DOI：
10.1121/1.403947
复制
发表时间：
1992-08-01
影响因子：
2.4
通讯作者：
TURNER, CW
中科院分区：
文献类型：
--
作者：
ZENG, FG;TURNER, CW
最近报道了一种非单调的强度判别函数，其中对于范围从20到100dBSPL的25ms正弦标准出现驼峰，并且在强烈的窄带噪声前向掩蔽之后出现100ms[F.-G.Zeng等人，Hear]。第55、223-230号决议(1991年)]。本文提供了关于前向掩蔽的三个因素如何影响中层驼峰的附加数据：信号延迟、掩码电平和频率。具体地说，在信号延迟50ms、200ms和400ms时，获得了强度上的刚刚可察觉的差异(JND)。结果表明，在中层，即使在400毫秒的信号延迟时，前向屏蔽强度JND也没有恢复到它们的未屏蔽值。信号延迟越长，这个中层驼峰就越小。这种中等水平JND的缓慢恢复与低自发频率(SR)神经元从前向掩蔽中恢复缓慢的发现一致[E.M.Relkin和J.R.Doucet，Hear。第55、215-222号决议(1991年)]。掩蔽水平从90dBSPL降至60dBSPL时，大中能级效应急剧减弱，当掩蔽水平低于40dBSPL时，大中能级效应消失。我们还观察到了大的中能级JND效应的频率选择性效应，因为频率分量远离信号频率2-3OCT的掩蔽器不影响JND效应。总体来说，目前的数据与曾等的假设是一致的。(1991)认为低SR神经元参与了前向掩蔽中强度辨别的中层驼峰。
A nonmonotonic intensity discrimination function was recently reported in which hump occurred for 25-ms sinusoidal standards ranging from 20 to 100 dB SPL and presented 100 ms after an intense narrow-band noise forward masker [F.-G. Zeng et al., Hear. Res. 55, 223-230 (1991)]. This paper provides additional data on how the midlevel hump is affected by three factors of forward masking: signal delay, masker level, and frequency. Specifically, just-noticeable differences (jnd's) in intensity were obtained at signal delays of 50, 200, and 400 ms. Results show that at the midlevels the forward-masked intensity jnd's did not recover to their unmasked values, even at the 400-ms signal delay. The longer the signal delay, the smaller this midlevel hump. This slow recovery of the midlevel jnd's is consistent with the finding that low-spontaneous rate (SR) neurons have a slow recovery from forward masking [E. M. Relkin and J. R. Doucet, Hear. Res. 55, 215-222 (1991)]. The large midlevel effect decreased sharply as masker level was reduced from 90 to 60 dB SPL, and disappeared for masker levels less than 40 dB SPL. A frequency selectivity effect for the large midlevel jnd effect was also observed, as maskers with frequency components 2 to 3 oct away from the signal frequency did not affect the jnd's. Overall, the present data are consistent with the hypothesis of Zeng et al. (1991) that low-SR neurons are involved in the midlevel hump of intensity discrimination in forward masking.