Functional Neuroimaging Laboratory, School of Psychology, University of Newcastle, Callaghan, New South Wales, Australia.
Priority Research Centre for Brain and Mental Health, University of Newcastle, Callaghan, New South Wales, Australia.
Hum Brain Mapp. 2021 Oct 1;42(14):4643-4657. doi: 10.1002/hbm.25573. Epub 2021 Jun 29.
During task-switching paradigms, both event-related potentials and time-frequency analyses show switch and mixing effects at frontal and parietal sites. Switch and mixing effects are associated with increased power in broad frontoparietal networks, typically stronger in the theta band (~4-8 Hz). However, it is not yet known whether mixing and switch costs rely upon common or distinct networks. In this study, we examine proactive and reactive control networks linked to task switching and mixing effects, and whether strength of connectivity in these networks is associated with behavioural outcomes. Participants (n = 197) completed a cued-trials task-switching paradigm with concurrent electroencephalography, after substantial task practice to establish strong cue-stimulus-response representations. We used inter-site phase clustering, a measure of functional connectivity across electrode sites, to establish cross-site connectivity from a frontal and a parietal seed. Distinct theta networks were activated during proactive and reactive control periods. During the preparation interval, mixing effects were associated with connectivity from the frontal seed to parietal sites, and switch effects with connectivity from the parietal seed to occipital sites. Lateralised occipital connectivity was common to both switch and mixing effects. After target onset, frontal and parietal seeds showed a similar pattern of connectivity across trial types. These findings are consistent with distinct and common proactive control networks and common reactive networks in highly practised task-switching performers.
在任务转换范式中，事件相关电位和时频分析都显示出额顶部位点的转换和混合效应。转换和混合效应与广泛的额顶网络中的功率增加有关，通常在 theta 频段（~4-8 Hz）更强。然而，目前尚不清楚混合和转换成本是否依赖于共同或不同的网络。在这项研究中，我们研究了与任务转换和混合效应相关的主动和反应性控制网络，以及这些网络中的连接强度是否与行为结果相关。参与者（n=197）在进行了大量任务练习以建立强大的提示-刺激-反应表示后，完成了一个带有同时进行的脑电图的提示试验任务转换范式。我们使用了站点间相位聚类，这是一种跨电极站点的功能连接测量方法，从额部和顶部分子建立了跨站点连接。在主动和反应性控制期间，激活了不同的 theta 网络。在准备间隔期间，混合效应与从额部种子到顶部位点的连接有关，而转换效应与从顶部位点到枕部的连接有关。偏侧枕部连接对转换和混合效应都很常见。在目标出现后，额叶和顶叶种子在不同的试验类型之间表现出相似的连接模式。这些发现与高度熟练的任务转换执行者中的不同和共同的主动控制网络和共同的反应性网络一致。
