Heinz Andrew J, Johnson Jeffrey S
Department of Psychology, North Dakota State UniversityFargo, ND, USA.
Center for Visual and Cognitive Neuroscience, North Dakota State UniversityFargo, ND, USA.
Front Hum Neurosci. 2017 May 15;11:250. doi: 10.3389/fnhum.2017.00250. eCollection 2017.
Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band power (ABP) during the delay period of verbal and visual working memory (VWM) tasks. There have been various proposals regarding the functional significance of such increases, including the inhibition of task-irrelevant cortical areas as well as the active retention of information in VWM. The present study examines the role of delay-period ABP in mediating the effects of interference arising from on-going visual processing during a concurrent VWM task. Specifically, we reasoned that, if set-size dependent increases in ABP represent the gating out of on-going task-irrelevant visual inputs, they should be predictive with respect to some modulation in visual evoked potentials resulting from a task-irrelevant delay period probe stimulus. In order to investigate this possibility, we recorded the electroencephalogram while subjects performed a change detection task requiring the retention of two or four novel shapes. On a portion of trials, a novel, task-irrelevant bilateral checkerboard probe was presented mid-way through the delay. Analyses focused on examining correlations between set-size dependent increases in ABP and changes in the magnitude of the P1, N1 and P3a components of the probe-evoked response and how such increases might be related to behavior. Results revealed that increased delay-period ABP was associated with changes in the amplitude of the N1 and P3a event-related potential (ERP) components, and with load-dependent changes in capacity when the probe was presented during the delay. We conclude that load-dependent increases in ABP likely play a role in supporting short-term retention by gating task-irrelevant sensory inputs and suppressing potential sources of disruptive interference.
探索神经振荡在认知中作用的研究表明，在言语和视觉工作记忆（VWM）任务的延迟期，α波段功率（ABP）持续增加。关于这种增加的功能意义有各种提议，包括抑制与任务无关的皮质区域以及在VWM中积极保留信息。本研究考察延迟期ABP在介导并发VWM任务期间正在进行的视觉处理产生的干扰效应中的作用。具体而言，我们推断，如果ABP中与集合大小相关的增加代表对正在进行的与任务无关的视觉输入的排除，那么它们应该能预测由与任务无关的延迟期探测刺激引起的视觉诱发电位的某些调制。为了研究这种可能性，我们在受试者执行需要保留两个或四个新形状的变化检测任务时记录脑电图。在一部分试验中，在延迟期中途呈现一个新的、与任务无关的双侧棋盘格探测刺激。分析集中于检查ABP中与集合大小相关的增加与探测诱发反应的P1、N1和P3a成分幅度变化之间的相关性，以及这种增加可能与行为如何相关。结果显示，延迟期ABP增加与N1和P3a事件相关电位（ERP）成分的幅度变化相关，并且当在延迟期呈现探测刺激时与容量的负荷依赖性变化相关。我们得出结论，ABP中负荷依赖性增加可能通过排除与任务无关的感觉输入和抑制潜在的干扰源在支持短期记忆方面发挥作用。
