Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
PLoS One. 2009 Nov 26;4(11):e8042. doi: 10.1371/journal.pone.0008042.
Although limited in capacity, visual working memory (VWM) plays an important role in many aspects of visually-guided behavior. Recent experiments have demonstrated an electrophysiological marker of VWM encoding and maintenance, the contralateral delay activity (CDA), which has been shown in multiple tasks that have both explicit and implicit memory demands. Here, we investigate whether the CDA is evident during visual search, a thoroughly-researched task that is a hallmark of visual attention but has no explicit memory requirements.
METHODOLOGY/PRINCIPAL FINDINGS: The results demonstrate that the CDA is present during a lateralized search task, and that it is similar in amplitude to the CDA observed in a change-detection task, but peaks slightly later. The changes in CDA amplitude during search were strongly correlated with VWM capacity, as well as with search efficiency. These results were paralleled by behavioral findings showing a strong correlation between VWM capacity and search efficiency.
CONCLUSIONS/SIGNIFICANCE: We conclude that the activity observed during visual search was generated by the same neural resources that subserve VWM, and that this activity reflects the maintenance of previously searched distractors.
尽管容量有限，视觉工作记忆（VWM）在许多视觉引导行为方面发挥着重要作用。最近的实验证明了 VWM 编码和维持的一种电生理标记，即对侧延迟活动（CDA），它在具有明确和隐含记忆要求的多项任务中都得到了证明。在这里，我们研究 CDA 是否在视觉搜索中明显，这是一个经过深入研究的任务，是视觉注意力的标志，但没有明确的记忆要求。
方法/主要发现：结果表明，CDA 存在于侧化搜索任务中，其幅度与在变化检测任务中观察到的 CDA 相似，但峰值稍晚。搜索过程中 CDA 幅度的变化与 VWM 容量以及搜索效率强烈相关。这些结果与行为学发现相平行，表明 VWM 容量与搜索效率之间存在很强的相关性。
结论/意义：我们的结论是，在视觉搜索中观察到的活动是由支持 VWM 的相同神经资源产生的，并且该活动反映了先前搜索到的分心物的维持。
