While previous works established the inhibitory role of alpha oscillations during working memory maintenance, it remains an open question whether such an inhibitory control is a top-down process. Here, we attempted to disentangle this issue by considering the spatiotemporal component of waves in the alpha band, i.e., alpha traveling waves. We reanalyzed two pre-existing and open-access EEG datasets (N = 180, 90 males, 80 females, 10 unknown) where participants performed lateralized, visual delayed match-to-sample working memory tasks. In the first dataset, the distractor load was manipulated (2, 4, or 6), whereas in the second dataset, the memory span varied between 1, 3, and 6 items. We focused on the propagation of alpha waves on the anterior-posterior axis during the retention period. Our results reveal an increase in alpha-band forward waves as the distractor load increased, but also an increase in forward waves and a decrease in backward waves as the memory set size increased. Our results also showed a lateralization effect: alpha forward waves exhibited a more pronounced increase in the hemisphere contralateral to the distractors, whereas the reduction in backward waves was stronger in the hemisphere contralateral to the targets. In short, the forward waves were regulated by distractors, whereas targets inversely modulated backward waves. Such a dissociation of goal-related and goal-irrelevant physiological signals suggests the coexistence of bottom-up and top-down inhibitory processes: alpha forward waves might convey a gating effect driven by distractor load, while backward waves may represent direct top-down gain control of downstream visual areas.

虽然以前的工作确立了 α 振荡在工作记忆维持过程中的抑制作用，但这种抑制控制是否是一个自上而下的过程仍然是一个悬而未决的问题。在这里，我们试图通过考虑 alpha 波段中波的时空分量（即 alpha 行波）来理清这个问题。我们重新分析了两个预先存在的开放访问脑电图数据集 （N = 180,90 名男性，80 名女性，10 名未知），其中参与者执行偏侧化、视觉延迟匹配与样本工作记忆任务。在第一个数据集中，干扰项负载纵（2、4 或 6），而在第二个数据集中，内存跨度在 1、3 和 6 个项目之间变化。我们专注于保留期内 α 波在前后轴上的传播。我们的结果显示，随着干扰物负载的增加，α 波段前向波增加，但随着内存集大小的增加，前向波的增加和后向波的减少。我们的结果还显示了偏侧化效应：α 前向波在牵引物对侧的半球表现出更明显的增加，而在目标对侧的半球，向后波的减少更强。简而言之，前向波受干扰物调节，而目标则逆向调制后向波。目标相关和目标无关的生理信号的这种解离表明自下而上和自上而下的抑制过程共存：α 正向波可能传达由牵引器负荷驱动的门控效应，而向后波可能代表下游视觉区域的直接自上而下的增益控制。