DISTORTION OF ERP AVERAGES DUE TO OVERLAP FROM TEMPORALLY ADJACENT ERPS - ANALYSIS AND CORRECTION
DISTORTION OF ERP AVERAGES DUE TO OVERLAP FROM TEMPORALLY ADJACENT ERPS - ANALYSIS AND CORRECTION
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DOI：
10.1111/j.1469-8986.1993.tb03209.x
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发表时间：
1993-01-01
期刊：
影响因子：
3.7
通讯作者：
WOLDORFF, MG
中科院分区：
文献类型：
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作者：
WOLDORFF, MG
在事件相关电位(ERPs)的研究中，短刺激间期(ISIS)常被用来研究某些神经或心理现象。然而，简而言之，事件相关电位对连续刺激的反应可能重叠，从而扭曲事件相关电位平均值。本文描述了一种信号处理方法，用于分析由于这种重叠而引起的事件相关电位平均值的失真。一般而言，根据由每种类型的相邻刺激引发的ERP波形的数学卷积来模拟失真，其中具有这些刺激相对于平均时段在时间上的对应分布。利用这一框架，研究了ERP重叠对实验设计和解释的一些影响，特别强调了选择性注意范式。结果表明，在短ISI实验中，由于事件相关电位重叠而引起混淆的可能性是普遍存在的，即使是广泛使用的刺激随机化程序也不一定能控制有注意刺激和无注意刺激的事件相关电位的不同失真。在短时ISI研究中，事件相关电位重叠引起的问题可能特别严重，这些研究考察了事件相关电位(和相关的知觉过程)如何受到先前刺激的性质(即刺激序列效应)的影响。提出了一套从记录的事件相关电位平均值中估计和消除因响应重叠而引起的残余失真的算法。这些算法的使用统称为相邻响应(ADJAR)技术，可以缓解在使用短ISIS时出现的许多与重叠相关的问题，从而增强ERP技术的能力。
In studies of event-related potentials (ERPs), short interstimulus intervals (ISIs) are often employed to investigate certain neural or psychological phenomena. At short ISIs, however, the ERP responses to successive stimuli may overlap, thereby distorting the ERP averages. This paper describes a signal processing approach for analyzing the distortion of ERP averages due to such overlap. In general, the distortion is modeled in terms of mathematical convolutions of the ERP waveform elicited by each type of adjacent stimulus with the corresponding distribution in time of those stimuli relative to the averaging epoch. Using this framework, a number of implications of ERP overlap for experimental design and interpretation are examined, with special emphasis given to selective attention paradigms. It is shown that the possibility of confound due to ERP overlap is widespread in short-ISI experiments, and even the widely used procedure of stimulus randomization does not necessarily control for differential distortion of the ERPs to attended versus inattended stimuli. Problems due to ERP overlap can be particularly serious in short-ISI studies that examine how ERPs (and associated perceptual processes) are influenced by the nature of the preceding stimulus (i.e., stimulus sequence effects). A set of algorithms is presented for estimating and removing the residual distortion due to response overlap from recorded ERP averages. The use of these algorithms, collectively termed the Adjacent Response (Adjar) Technique, can alleviate many of the overlap-related problems that arise when short ISIs are used, thereby enhancing the power of the ERP technique.