Ikkai Akiko, McCollough Andrew W, Vogel Edward K
Department of Psychology, New York University, New York, USA.
J Neurophysiol. 2010 Apr;103(4):1963-8. doi: 10.1152/jn.00978.2009. Epub 2010 Feb 10.
Visual working memory (VWM) helps to temporarily represent information from the visual environment and is severely limited in capacity. Recent work has linked various forms of neural activity to the ongoing representations in VWM. One piece of evidence comes from human event-related potential studies, which find a sustained contralateral negativity during the retention period of VWM tasks. This contralateral delay activity (CDA) has previously been shown to increase in amplitude as the number of memory items increases, up to the individual's working memory capacity limit. However, significant alternative hypotheses remain regarding the true nature of this activity. Here we test whether the CDA is modulated by the perceptual requirements of the memory items as well as whether it is determined by the number of locations that are being attended within the display. Our results provide evidence against these two alternative accounts and instead strongly support the interpretation that this activity reflects the current number of objects that are being represented in VWM.
视觉工作记忆（VWM）有助于临时表征来自视觉环境的信息，且容量极为有限。近期研究将各种形式的神经活动与VWM中持续的表征联系起来。一条证据来自人类事件相关电位研究，该研究发现在VWM任务的保持期会出现持续的对侧负波。此前已表明，这种对侧延迟活动（CDA）的幅度会随着记忆项目数量的增加而增大，直至达到个体的工作记忆容量极限。然而，关于这种活动的真实性质仍存在重要的替代假说。在此，我们测试CDA是否受记忆项目的感知要求调节，以及它是否由显示中被关注的位置数量决定。我们的结果提供了反对这两种替代解释的证据，相反，有力地支持了这种活动反映VWM中当前所表征物体数量的解释。
