前体水平与时间效应之间的关系。
The relationship between precursor level and the temporal effect.
作者信息
Strickland Elizabeth A
机构信息
Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907-2038, USA.
出版信息
J Acoust Soc Am. 2008 Feb;123(2):946-54. doi: 10.1121/1.2821977.
Previous studies have suggested that temporal effects in masking may be consistent with a decrease in cochlear gain. One paradigm used to show this is to measure the level of a long-duration masker required to just mask a short-duration tone that occurs near masker onset. The temporal effect is revealed when the signal is detected at a lower signal-to-noise ratio following preceding stimulation (either an extension of the masker or a separate precursor). The present study examined whether this effect depends on precursor level. The signal was a 10-ms, 4-kHz tone. The masker was 200 ms. A fixed-level precursor had the same frequency characteristics as the masker, and was 205 ms. The masker and precursor had either no notch or a wide notch about the signal frequency. For a given precursor level, the growth of masker level with signal level was determined. These data were used to estimate input-output functions. The results are consistent with a graded decrease in gain at the signal frequency when there is no notch in the masker and precursor, and a graded decrease in suppression when there is a large notch. These results could be consistent with the action of the medial olivocochlear reflex.
以往的研究表明，掩蔽中的时间效应可能与耳蜗增益的降低相一致。用于证明这一点的一种范式是测量刚好能掩蔽在掩蔽音开始附近出现的短持续时间纯音所需的长持续时间掩蔽音的电平。当前刺激（掩蔽音的延长或单独的前导刺激）之后，当以较低的信噪比检测到信号时，时间效应就会显现出来。本研究考察了这种效应是否取决于前导刺激的电平。信号为10毫秒、4千赫的纯音。掩蔽音为200毫秒。固定电平的前导刺激与掩蔽音具有相同的频率特性，时长为205毫秒。掩蔽音和前导刺激在信号频率处要么没有陷波，要么有一个宽陷波。对于给定的前导刺激电平，确定掩蔽音电平随信号电平的增长情况。这些数据用于估计输入-输出函数。结果表明，当掩蔽音和前导刺激中没有陷波时，信号频率处的增益呈分级下降；当有一个大陷波时，抑制作用呈分级下降。这些结果可能与内侧橄榄耳蜗反射的作用一致。
Zotero 插件