Functional Neuroimaging Laboratory, School of Psychology, University of Newcastle, Callaghan, NSW, Australia.
Priority Research Centre for Brain and Mental Health, University of Newcastle, Callaghan, NSW, Australia.
Psychophysiology. 2020 May;57(5):e13533. doi: 10.1111/psyp.13533. Epub 2020 Jan 29.
Event-related potentials (ERPs) and total time-frequency power analyses have shown that performance costs during task switching are related to differential preparation to switch tasks (switch cost) and repeat the same task (mixing cost) during both proactive control (cue-to-target interval; CTI) and reactive control (post-target). The time-frequency EEG signal is comprised of both phase-locked activity (associated with stimulus-specific processes) and nonphase-locked activity (represents processes thought to persist over longer timeframes and do not contribute to the average ERP). In the present study, we used a cued task-switching paradigm to examine whether phase-locked and nonphase-locked power are differentially modulated by switch and mixing effects in intervals associated with the need for proactive control (CTI) and reactive control (post-target interval). Phase-locked activity was observed in the theta and alpha bands, closely resembled that seen for total power, and was consistent with switch and mixing ERP positivities. Nonphase-locked analyses showed theta and alpha power effects for both switch and mixing effects early in the CTI and as well as more sustained alpha and beta activity around cue onset, and extending from mid-CTI into the post-target interval. Nonphase-locked activity in pretarget alpha and posttarget theta power were both correlated with response time mixing cost. These findings provide novel insight into phase-locked and nonphase-locked activity associated with switch and mixing costs that are not evident with ERP or total time-frequency analyses.
事件相关电位 (ERPs) 和总时频功率分析表明，任务切换过程中的表现成本与任务切换的差异准备（切换成本）和在主动控制（提示到目标间隔；CTI）和反应控制（目标后）期间重复相同任务（混合成本）有关。时频 EEG 信号由锁相活动（与刺激特定过程相关）和非锁相活动（代表被认为持续时间较长且不会对平均 ERP 做出贡献的过程）组成。在本研究中，我们使用提示任务切换范式来检查锁相和非锁相功率是否在与主动控制（CTI）和反应控制（目标后间隔）相关的间隔中受到切换和混合效应的差异调节。在 theta 和 alpha 波段观察到锁相活动，与总功率观察到的非常相似，与切换和混合 ERP 正性一致。非锁相分析显示 CTI 早期以及提示开始时出现 theta 和 alpha 功率效应，以及 cue 后 CTI 进入目标后间隔时持续的 alpha 和 beta 活动。目标前 alpha 和目标后 theta 功率的非锁相活动都与混合反应时间成本相关。这些发现为与切换和混合成本相关的锁相和非锁相活动提供了新的见解，这些活动在 ERP 或总时频分析中并不明显。
