Storage in Visual Working Memory Recruits a Content-Independent Pointer System
通过脑电图记录发现，视觉工作记忆存储时存在一种与内容无关的负荷敏感神经活动，能追踪存储项目数量并预测个体记忆容量差异，表明存在一个容量有限的指针系统。
Past work has shown that storage in working memory elicits stimulus-specific neural activity that tracks the stored content. Here, we present evidence for a distinct class of load-sensitive neural activity that indexes items without representing their contents per se. We recorded electroencephalogram (EEG) activity while adult human subjects stored varying numbers of items in visual working memory. Multivariate analysis of the scalp topography of EEG voltage enabled precise tracking of the number of individuated items stored and robustly predicted individual differences in working memory capacity. Critically, this signature of working memory load generalized across variations in both the type and number of visual features stored about each item, suggesting that it tracked the number of individuated memory representations and not the content of those memories. We hypothesize that these findings reflect the operation of a capacity-limited pointer system that supports on-line storage and attentive tracking.