Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou 310000, China.
State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute of Brain Research, Beijing Normal University, Beijing 100875, China.
eNeuro. 2024 Nov 14;11(11). doi: 10.1523/ENEURO.0265-24.2024. Print 2024 Nov.
Visual working memory (VWM) requires precise feature binding. Previous studies have revealed a close relationship between the posterior parietal cortex (PPC) and feature binding during VWM; this study further examined their causal relationship through three transcranial direct current stimulation (tDCS) experiments. In Experiment 1 ( = 57), participants underwent three sessions of tDCS separately, including PPC stimulation, occipital cortex stimulation, and sham stimulation, and completed delayed estimation tasks for orientations before and after stimulation. Results showed that tDCS over PPC selectively prolonged recall response time (RT) and increased the probability of nontarget responses (a.k.a. failure of feature binding, NT). In Experiment 2 ( = 29), combining metacognition estimation, we further investigated whether the effects of PPC stimulation were attributed to misbinding (i.e., participants self-reported "remembered" in nontarget responses) or informed guessing trials (participants self-reported "forgotten" in nontarget responses). We replicated the main findings in Experiment 1 and observed greater tDCS effects of PPC on RT in informed guessing trials while there are comparable effects on NT in these two types of trials. In Experiment 3 ( = 28), we then examined whether the tDCS effects over PPC specifically influenced the memory retrieval process by using a change detection task. We found that PPC stimulation did not influence the recognition RT or accuracy. Together, this study provided direct causal evidence supporting the specific involvement of PPC in feature binding during VWM retrieval, from both aspects of speed and response preference, expanding our understanding of the neural basis of feature binding in VWM.
视觉工作记忆（VWM）需要精确的特征绑定。先前的研究揭示了后顶叶皮层（PPC）与 VWM 期间特征绑定之间的密切关系；本研究通过三个经颅直流电刺激（tDCS）实验进一步探讨了它们之间的因果关系。在实验 1（ = 57）中，参与者分别接受了三次 tDCS 刺激，包括 PPC 刺激、枕叶皮层刺激和假刺激，并在刺激前后完成了方向的延迟估计任务。结果表明，PPC 上的 tDCS 选择性地延长了回忆反应时间（RT），并增加了非目标反应的概率（也称为特征绑定失败，NT）。在实验 2（ = 29）中，结合元认知估计，我们进一步研究了 PPC 刺激的效果是否归因于错误绑定（即参与者在非目标反应中自我报告“记得”）或信息猜测试验（参与者在非目标反应中自我报告“忘记”）。我们在实验 1 中复制了主要发现，并观察到在信息猜测试验中，PPC 刺激对 RT 的 tDCS 效应更大，而在这两种类型的试验中，NT 的效应相当。在实验 3（ = 28）中，我们通过使用变化检测任务进一步检查了 PPC 上的 tDCS 效应是否特别影响记忆检索过程。我们发现，PPC 刺激并不影响识别 RT 或准确性。总之，这项研究提供了直接的因果证据，支持 PPC 在 VWM 检索过程中的特征绑定中特定的参与，从速度和反应偏好两个方面扩展了我们对 VWM 中特征绑定的神经基础的理解。
