Slugocki Christopher, Bosnyak Daniel, Trainor Laurel J
Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada.
Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada; Rotman Research Institute, Baycrest Hospital, Toronto, Ontario, Canada.
Hear Res. 2017 Mar;345:30-42. doi: 10.1016/j.heares.2016.12.014. Epub 2016 Dec 31.
Recent electrophysiological work has evinced a capacity for plasticity in subcortical auditory nuclei in human listeners. Similar plastic effects have been measured in cortically-generated auditory potentials but it is unclear how the two interact. Here we present Simultaneously-Evoked Auditory Potentials (SEAP), a method designed to concurrently elicit electrophysiological brain potentials from inferior colliculus, thalamus, and primary and secondary auditory cortices. Twenty-six normal-hearing adult subjects (mean 19.26 years, 9 male) were exposed to 2400 monaural (right-ear) presentations of a specially-designed stimulus which consisted of a pure-tone carrier (500 or 600 Hz) that had been amplitude-modulated at the sum of 37 and 81 Hz (depth 100%). Presentation followed an oddball paradigm wherein the pure-tone carrier was set to 500 Hz for 85% of presentations and pseudo-randomly changed to 600 Hz for the remaining 15% of presentations. Single-channel electroencephalographic data were recorded from each subject using a vertical montage referenced to the right earlobe. We show that SEAP elicits a 500 Hz frequency-following response (FFR; generated in inferior colliculus), 80 (subcortical) and 40 (primary auditory cortex) Hz auditory steady-state responses (ASSRs), mismatch negativity (MMN) and P3a (when there is an occasional change in carrier frequency; secondary auditory cortex) in addition to the obligatory N1-P2 complex (secondary auditory cortex). Analyses showed that subcortical and cortical processes are linked as (i) the latency of the FFR predicts the phase delay of the 40 Hz steady-state response, (ii) the phase delays of the 40 and 80 Hz steady-state responses are correlated, and (iii) the fidelity of the FFR predicts the latency of the N1 component. The SEAP method offers a new approach for measuring the dynamic encoding of acoustic features at multiple levels of the auditory pathway. As such, SEAP is a promising tool with which to study how relationships between subcortical and cortical processes change through early development and auditory learning as well as by hearing loss and aging.
最近的电生理研究表明，人类听众的皮层下听觉核具有可塑性。在皮层产生的听觉电位中也测量到了类似的可塑性效应，但尚不清楚两者是如何相互作用的。在这里，我们介绍了同时诱发听觉电位（SEAP），这是一种旨在同时从下丘、丘脑以及初级和次级听觉皮层引出脑电生理电位的方法。26名听力正常的成年受试者（平均年龄19.26岁，9名男性）接受了2400次单耳（右耳）呈现的特殊设计刺激，该刺激由一个纯音载波（500或600赫兹）组成，其幅度以37和81赫兹之和进行调制（深度100%）。呈现遵循oddball范式，其中纯音载波在85%的呈现中设置为500赫兹，并在其余15%的呈现中伪随机变为600赫兹。使用以右耳垂为参考的垂直导联记录每个受试者的单通道脑电图数据。我们表明，SEAP除了诱发必不可少的N1 - P2复合波（次级听觉皮层）外，还能诱发500赫兹频率跟随反应（FFR；在下丘产生）、80（皮层下）和40（初级听觉皮层）赫兹听觉稳态反应（ASSR）、失配负波（MMN）和P3a（当载波频率偶尔变化时；次级听觉皮层）。分析表明，皮层下和皮层过程是相关的，因为（i）FFR的潜伏期预测40赫兹稳态反应的相位延迟，（ii）40和80赫兹稳态反应的相位延迟相关，以及（iii）FFR的保真度预测N1成分的潜伏期。SEAP方法为测量听觉通路多个层面上声学特征的动态编码提供了一种新方法。因此，SEAP是一种很有前景的工具，可用于研究皮层下和皮层过程之间的关系如何通过早期发育、听觉学习以及听力损失和衰老而发生变化。
