Department of Psychology, Lancaster University, Lancaster, LA1 4YF, UK.
J Assoc Res Otolaryngol. 2011 Feb;12(1):89-100. doi: 10.1007/s10162-010-0236-1. Epub 2010 Sep 28.
Practice can lead to dramatic improvements in the discrimination of auditory stimuli. In this study, we investigated changes of the frequency-following response (FFR), a subcortical component of the auditory evoked potentials, after a period of pitch discrimination training. Twenty-seven adult listeners were trained for 10 h on a pitch discrimination task using one of three different complex tone stimuli. One had a static pitch contour, one had a rising pitch contour, and one had a falling pitch contour. Behavioral measures of pitch discrimination and FFRs for all the stimuli were measured before and after the training phase for these participants, as well as for an untrained control group (n = 12). Trained participants showed significant improvements in pitch discrimination compared to the control group for all three trained stimuli. These improvements were partly specific for stimuli with the same pitch modulation (dynamic vs. static) and with the same pitch trajectory (rising vs. falling) as the trained stimulus. Also, the robustness of FFR neural phase locking to the sound envelope increased significantly more in trained participants compared to the control group for the static and rising contour, but not for the falling contour. Changes in FFR strength were partly specific for stimuli with the same pitch modulation (dynamic vs. static) of the trained stimulus. Changes in FFR strength, however, were not specific for stimuli with the same pitch trajectory (rising vs. falling) as the trained stimulus. These findings indicate that even relatively low-level processes in the mature auditory system are subject to experience-related change.
经过一段时间的音高辨别训练，听觉刺激的辨别能力可以得到显著提高。在这项研究中，我们调查了在音高辨别训练后，听觉诱发电位的亚皮质成分——频率跟随反应（FFR）的变化。 27 名成年被试者接受了为期 10 小时的基于三种不同复合音刺激的音高辨别任务训练。其中一个刺激具有静态音高轮廓，一个具有上升的音高轮廓，一个具有下降的音高轮廓。在训练前后，对这些被试者（以及未接受训练的对照组 12 人）的所有刺激的音高辨别行为测量和 FFR 进行了测量。与对照组相比，接受训练的被试者在所有三种训练刺激下的音高辨别能力都有显著提高。这些提高在某种程度上是针对具有相同音调制（动态与静态）和相同音轨迹（上升与下降）的刺激的。此外，与对照组相比，FFR 对声音包络的神经相位锁定的稳健性在接受训练的被试者中显著提高，这在静态和上升轮廓的刺激中更为明显，但在下降轮廓的刺激中则不然。FFR 强度的变化在某种程度上是针对与训练刺激具有相同音调制（动态与静态）的刺激的。然而，FFR 强度的变化并不针对与训练刺激具有相同音轨迹（上升与下降）的刺激。这些发现表明，即使是成熟听觉系统中的相对较低水平的过程也会受到经验相关的变化。
