Dealing with ocular artifacts on lateralized ERPs in studies of visual-spatial attention and memory: ICA correction versus epoch rejection
Dealing with ocular artifacts on lateralized ERPs in studies of visual-spatial attention and memory: ICA correction versus epoch rejection
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DOI：
10.1111/psyp.12675
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发表时间：
2017-01-01
期刊：
影响因子：
3.7
通讯作者：
Jolicoeur, Pierre
中科院分区：
文献类型：
--
作者：
Drisdelle, Brandi Lee;Aubin, Sebrina;Jolicoeur, Pierre
本研究的目的是评估的鲁棒性和可靠性的独立成分分析（伊卡）的视觉空间注意和记忆的电生理研究中的眼伪影校正的方法。N2 pc和持续后对侧负波（SPCN）分别是视觉空间注意和记忆的电生理标志物，是通常在呈现横向刺激（目标和干扰物）后观察到的侧化后ERP，沿着在整个试验中保持视觉搜索中心的注视。传统上，受试者可能已经转移了他们的视线的试验基于截止阈值被拒绝，从而最小化由扫视引起的电生理污染。考虑到拒绝导致的数据丢失，我们通过比较使用标准固定指令的结果与受试者被指示将目光转向可能的目标的条件来检查眼睛矫正。这两种情况进行了分析，使用拒绝阈值和伊卡校正眼跳活动管理。结果表明，伊卡保存的数据，否则将被删除，并留下完整的基础神经活动，如先前所示的实验操作，以调节N2 pc和SPCN。伊卡不仅能挽救数据而不会扭曲数据，而且大的眼球运动也只有微妙的影响。总的来说，研究结果不仅为特殊情况下的伊卡校正提供了令人信服的证据（例如，受试者不遵循注视指令），而且在对视觉-空间注意力和记忆感兴趣的电生理学研究中作为标准眼伪影管理的候选者。
The objective of the present study was to assess the robustness and reliability of independent component analysis (ICA) as a method for ocular artifact correction in electrophysiological studies of visual-spatial attention and memory. The N2pc and sustained posterior contralateral negativity (SPCN), electrophysiological markers of visual-spatial attention and memory, respectively, are lateralized posterior ERPs typically observed following the presentation of lateral stimuli (targets and distractors) along with instructions to maintain fixation on the center of the visual search for the entire trial. Traditionally, trials in which subjects may have displaced their gaze are rejected based on a cutoff threshold, minimizing electrophysiological contamination by saccades. Given the loss of data resulting from rejection, we examined ocular correction by comparing results using standard fixation instructions against a condition where subjects were instructed to shift their gaze toward possible targets. Both conditions were analyzed using a rejection threshold and ICA correction for saccade activity management. Results demonstrate that ICA conserves data that would have otherwise been removed and leaves the underlying neural activity intact, as demonstrated by experimental manipulations previously shown to modulate the N2pc and the SPCN. Not only does ICA salvage and not distort data, but also large eye movements had only subtle effects. Overall, the findings provide convincing evidence for ICA correction for not only special cases (e.g., subjects did not follow fixation instruction) but also as a candidate for standard ocular artifact management in electrophysiological studies interested in visual-spatial attention and memory.