Pessoa Luiz, Gutierrez Eva, Bandettini Peter, Ungerleider Leslie
Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
Neuron. 2002 Aug 29;35(5):975-87. doi: 10.1016/s0896-6273(02)00817-6.
We used fMRI to investigate how moment-to-moment neural activity contributes to success or failure on individual trials of a visual working memory (WM) task. We found that different nodes of a distributed cortical network were activated to a greater extent for correct compared to incorrect trials during stimulus encoding, memory maintenance during delays, and at test. A logistic regression analysis revealed that the fMRI signal amplitude during the delay interval in a network of frontoparietal regions predicted successful performance on a trial-by-trial basis. Differential delay activity occurred even for only those trials in which BOLD activity during encoding was strong, demonstrating that it was not a simple consequence of effective versus ineffective encoding. Our results indicate that accurate memory depends on strong sustained signals that span the delay interval of WM tasks.
我们使用功能磁共振成像（fMRI）来研究瞬间神经活动如何在视觉工作记忆（WM）任务的各个试验中促成成功或失败。我们发现，在刺激编码、延迟期间的记忆维持以及测试过程中，与错误试验相比，分布式皮质网络的不同节点在正确试验中被激活的程度更高。逻辑回归分析表明，额顶叶区域网络在延迟间隔期间的fMRI信号幅度能够逐试验预测成功表现。即使仅针对那些编码期间BOLD活动较强的试验，也会出现差异延迟活动，这表明它并非有效编码与无效编码的简单结果。我们的结果表明，准确的记忆依赖于跨越WM任务延迟间隔的强烈持续信号。
