Lalor Edmund C, Power Alan J, Reilly Richard B, Foxe John J
Trinity College Institute of Neuroscience, School of Engineering, Trinity College Dublin, Printing House, College Green, Dublin 2, Ireland.
J Neurophysiol. 2009 Jul;102(1):349-59. doi: 10.1152/jn.90896.2008. Epub 2009 May 13.
In natural environments complex and continuous auditory stimulation is virtually ubiquitous. The human auditory system has evolved to efficiently process an infinity of everyday sounds, which range from short, simple bursts of noise to signals with a much higher order of information such as speech. Investigation of temporal processing in this system using the event-related potential (ERP) technique has led to great advances in our knowledge. However, this method is restricted by the need to present simple, discrete, repeated stimuli to obtain a useful response. Alternatively the continuous auditory steady-state response is used, although this method reduces the evoked response to its fundamental frequency component at the expense of useful information on the timing of response transmission through the auditory system. In this report, we describe a method for eliciting a novel ERP, which circumvents these limitations, known as the AESPA (auditory-evoked spread spectrum analysis). This method uses rapid amplitude modulation of audio carrier signals to estimate the impulse response of the auditory system. We show AESPA responses with high signal-to-noise ratios obtained using two types of carrier wave: a 1-kHz tone and broadband noise. To characterize these responses, they are compared with auditory-evoked potentials elicited using standard techniques. A number of similarities and differences between the responses are noted and these are discussed in light of the differing stimulation and analysis methods used. Data are presented that demonstrate the generalizability of the AESPA method and a number of applications are proposed.
在自然环境中，复杂且持续的听觉刺激几乎无处不在。人类听觉系统已经进化到能够高效处理无数日常声音，这些声音范围从短暂、简单的噪声突发到具有更高信息阶次的信号，如语音。使用事件相关电位（ERP）技术对该系统的时间处理进行研究，使我们的知识有了很大进展。然而，这种方法受到限制，因为需要呈现简单、离散、重复的刺激才能获得有用的反应。另一种方法是使用连续听觉稳态反应，尽管这种方法以牺牲通过听觉系统传输反应时间的有用信息为代价，将诱发反应降低到其基频成分。在本报告中，我们描述了一种引出新型ERP的方法，该方法规避了这些限制，称为听觉诱发扩频分析（AESPA）。这种方法使用音频载波信号的快速幅度调制来估计听觉系统的脉冲响应。我们展示了使用两种载波获得的具有高信噪比的AESPA反应：1kHz音调和平带噪声。为了表征这些反应，将它们与使用标准技术引出的听觉诱发电位进行比较。注意到反应之间的一些异同，并根据所使用的不同刺激和分析方法进行了讨论。给出的数据证明了AESPA方法的通用性，并提出了一些应用。
