Nikolaev Andrey R, Meghanathan Radha Nila, van Leeuwen Cees
Laboratory for Perceptual Dynamics, Brain & Cognition Research Unit, KU Leuven - University of Leuven, Leuven, Belgium.
Laboratory for Perceptual Dynamics, Brain & Cognition Research Unit, KU Leuven - University of Leuven, Leuven, Belgium.
Brain Cogn. 2016 Aug;107:55-83. doi: 10.1016/j.bandc.2016.06.004. Epub 2016 Jun 29.
Co-registration of EEG and eye movement has promise for investigating perceptual processes in free viewing conditions, provided certain methodological challenges can be addressed. Most of these arise from the self-paced character of eye movements in free viewing conditions. Successive eye movements occur within short time intervals. Their evoked activity is likely to distort the EEG signal during fixation. Due to the non-uniform distribution of fixation durations, these distortions are systematic, survive across-trials averaging, and can become a source of confounding. We illustrate this problem with effects of sequential eye movements on the evoked potentials and time-frequency components of EEG and propose a solution based on matching of eye movement characteristics between experimental conditions. The proposal leads to a discussion of which eye movement characteristics are to be matched, depending on the EEG activity of interest. We also compare segmentation of EEG into saccade-related epochs relative to saccade and fixation onsets and discuss the problem of baseline selection and its solution. Further recommendations are given for implementing EEG-eye movement co-registration in free viewing conditions. By resolving some of the methodological problems involved, we aim to facilitate the transition from the traditional stimulus-response paradigm to the study of visual perception in more naturalistic conditions.
脑电图（EEG）与眼动的共同记录对于研究自由观看条件下的感知过程具有前景，前提是某些方法学挑战能够得到解决。其中大多数挑战源于自由观看条件下眼动的自主节奏特性。连续的眼动在短时间间隔内发生。它们诱发的活动在注视期间可能会扭曲EEG信号。由于注视持续时间的分布不均匀，这些扭曲是系统性的，在试验间平均后仍然存在，并且可能成为混淆的来源。我们通过顺序眼动对EEG诱发电位和时频成分的影响来说明这个问题，并提出一种基于实验条件之间眼动特征匹配的解决方案。该提议引发了关于根据感兴趣的EEG活动应匹配哪些眼动特征的讨论。我们还比较了相对于扫视和注视起始将EEG分割为与扫视相关的时段，并讨论了基线选择问题及其解决方案。对于在自由观看条件下实施EEG - 眼动共同记录给出了进一步的建议。通过解决一些相关的方法学问题，我们旨在促进从传统的刺激 - 反应范式向更自然条件下视觉感知研究的转变。
