Balaban Halely, Luria Roy
Sagol School of Neuroscience and School of Psychological Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
J Neurosci. 2017 Feb 1;37(5):1225-1239. doi: 10.1523/JNEUROSCI.2789-16.2016. Epub 2016 Dec 23.
Visual working memory (VWM) guides behavior by holding a set of active representations and modifying them according to changes in the environment. This updating process relies on a unique mapping between each VWM representation and an actual object in the environment. Here, we destroyed this mapping by either presenting a coherent object but then breaking it into independent parts or presenting an object but then abruptly replacing it with a different object. This allowed us to introduce the neural marker and behavioral consequence of an online resetting process in humans' VWM. Across seven experiments, we demonstrate that this resetting process involves abandoning the old VWM contents because they no longer correspond to the objects in the environment. Then, VWM encodes the novel information and reestablishes the correspondence between the new representations and the objects. The resetting process was marked by a unique neural signature: a sharp drop in the amplitude of the electrophysiological index of VWM contents (the contralateral delay activity), presumably indicating the loss of the existent object-to-representation mappings. This marker was missing when an updating process occurred. Moreover, when tracking moving items, VWM failed to detect salient changes in the object's shape when these changes occurred during the resetting process. This happened despite the object being fully visible, presumably because the mapping between the object and a VWM representation was lost. Importantly, we show that resetting, its neural marker, and the behavioral cost it entails, are specific to situations that involve a destruction of the objects-to-representations correspondence.
Visual working memory (VWM) maintains task-relevant information in an online state. Previous studies showed that VWM representations are accessed and modified after changes in the environment. Here, we show that this updating process critically depends on an ongoing mapping between the representations and the objects in the environment. When this mapping breaks, VWM cannot access the old representations and instead resets. The novel resetting process that we introduce removes the existing representations instead of modifying them and this process is accompanied by a unique neural marker. During the resetting process, VWM was blind to salient changes in the object's shape. The resetting process highlights the flexibility of our cognitive system in handling the dynamic environment by abruptly abandoning irrelevant schemas.
视觉工作记忆（VWM）通过保持一组活跃表征并根据环境变化对其进行修改来引导行为。这种更新过程依赖于每个VWM表征与环境中实际物体之间的独特映射。在此，我们通过以下方式破坏这种映射：要么呈现一个连贯的物体，然后将其分解为独立部分；要么呈现一个物体，然后突然用另一个不同的物体替换它。这使我们能够引入人类VWM中在线重置过程的神经标记和行为后果。在七个实验中，我们证明这种重置过程涉及摒弃旧的VWM内容，因为它们不再与环境中的物体相对应。然后，VWM对新信息进行编码，并重新建立新表征与物体之间的对应关系。重置过程以一种独特的神经特征为标志：VWM内容的电生理指标（对侧延迟活动）的幅度急剧下降，大概表明现存的物体到表征映射的丧失。当发生更新过程时，这个标记不存在。此外，在跟踪移动项目时，当这些变化在重置过程中发生时，VWM未能检测到物体形状的显著变化。尽管物体完全可见，但仍会出现这种情况，大概是因为物体与VWM表征之间的映射丢失了。重要的是，我们表明重置、其神经标记以及它所带来的行为代价，特定于涉及物体到表征对应关系被破坏的情况。
视觉工作记忆（VWM）在在线状态下维持与任务相关的信息。先前的研究表明，VWM表征在环境变化后会被访问和修改。在此，我们表明这种更新过程关键取决于表征与环境中物体之间正在进行的映射。当这种映射中断时，VWM无法访问旧的表征，而是进行重置。我们引入的新颖重置过程会移除现有的表征而不是对其进行修改，并且这个过程伴随着一个独特的神经标记。在重置过程中，VWM对物体形状的显著变化视而不见。重置过程通过突然摒弃不相关的模式突出了我们认知系统在处理动态环境时的灵活性。
