Mahajan Yatin, Peter Varghese, Sharma Mridula
The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Penrith, NSW, Australia.
The HEARing CRC, Melbourne, VIC, Australia.
Front Neurosci. 2017 Oct 10;11:560. doi: 10.3389/fnins.2017.00560. eCollection 2017.
Auditory event-related potentials (ERPs) have consistently been used in the investigation of auditory and cognitive processing in the research and clinical laboratories. There is currently no consensus on the choice of appropriate reference for auditory ERPs. The most commonly used references in auditory ERP research are the mathematically linked-mastoids (LM) and average referencing (AVG). Since LM and AVG referencing procedures do not solve the issue of electrically-neutral reference, Reference Electrode Standardization Technique (REST) was developed to create a neutral reference for EEG recordings. The aim of the current research is to compare the influence of the reference on amplitude and latency of auditory mismatch negativity (MMN) as a function of magnitude of frequency deviance across three commonly used electrode montages (16, 32, and 64-channel) using REST, LM, and AVG reference procedures. The current study was designed to determine if the three reference methods capture the variation in amplitude and latency of MMN with the deviance magnitude. We recorded MMN from 12 normal hearing young adults in an auditory oddball paradigm with 1,000 Hz pure tone as standard and 1,030, 1,100, and 1,200 Hz as small, medium and large frequency deviants, respectively. The EEG data recorded to these sounds was re-referenced using REST, LM, and AVG methods across 16-, 32-, and 64-channel EEG electrode montages. Results revealed that while the latency of MMN decreased with increment in frequency of deviant sounds, no effect of frequency deviance was present for amplitude of MMN. There was no effect of referencing procedure on the experimental effect tested. The amplitude of MMN was largest when the ERP was computed using LM referencing and the REST referencing produced the largest amplitude of MMN for 64-channel montage. There was no effect of electrode-montage on AVG referencing induced ERPs. Contrary to our predictions, the results suggest that the auditory MMN elicited as a function of increments in frequency deviance does not depend on the choice of referencing procedure. The results also suggest that auditory ERPs generated using REST referencing is contingent on the electrode arrays more than the AVG referencing.
听觉事件相关电位（ERPs）一直被用于研究和临床实验室中听觉与认知加工的研究。目前对于听觉ERPs合适参考电极的选择尚无共识。听觉ERP研究中最常用的参考电极是数学关联乳突电极（LM）和平均参考电极（AVG）。由于LM和AVG参考电极设置方法并不能解决电中性参考电极的问题，因此开发了参考电极标准化技术（REST）来为脑电图记录创建一个中性参考电极。本研究的目的是比较使用REST、LM和AVG参考电极设置方法时，在三种常用电极导联（16通道、32通道和64通道）下，参考电极对听觉失匹配负波（MMN）的幅度和潜伏期的影响，该影响是频率偏差幅度的函数。本研究旨在确定这三种参考电极方法是否能捕捉到MMN幅度和潜伏期随偏差幅度的变化。我们在听觉oddball范式中记录了12名听力正常的年轻成年人的MMN，以1000 Hz纯音为标准音，并分别以1030 Hz、1100 Hz和1200 Hz作为小、中、大频率偏差音。记录这些声音的脑电图数据通过REST、LM和AVG方法在16通道、32通道和64通道脑电图电极导联上进行重新参考电极设置。结果显示，虽然MMN的潜伏期随着偏差声音频率的增加而缩短，但MMN的幅度不存在频率偏差效应。参考电极设置方法对所测试实验效应没有影响。当使用LM参考电极设置计算ERP时，MMN的幅度最大，而REST参考电极设置在64通道导联中产生了最大的MMN幅度。电极导联对AVG参考电极设置诱发的ERP没有影响。与我们的预测相反，结果表明，作为频率偏差增加的函数而诱发的听觉MMN并不依赖于参考电极设置方法的选择。结果还表明，使用REST参考电极设置生成的听觉ERPs比AVG参考电极设置更依赖于电极阵列。
