Peters Benjamin, Bledowski Christoph, Rieder Maria, Kaiser Jochen
Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany.
Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany.
Brain Res. 2016 Jun 1;1640(Pt B):232-42. doi: 10.1016/j.brainres.2015.12.006. Epub 2015 Dec 10.
Processing of auditory spatial and non-spatial information in working memory has been shown to rely on separate cortical systems. While previous studies have demonstrated differences in spatial versus non-spatial processing from the encoding of to-be-remembered stimuli onwards, here we investigated whether such differences would be detectable already prior to presentation of the sample stimulus. We analyzed broad-band magnetoencephalography data from 15 healthy adults during an auditory working memory paradigm starting with a visual cue indicating the task-relevant stimulus feature for a given trial (lateralization or pitch) and a subsequent 1.5-s pre-encoding phase. This was followed by a sample sound (0.2s), the delay phase (0.8s) and a test stimulus (0.2s) after which participants made a match/non-match decision. Linear discriminant functions were trained to decode task-specific signal patterns throughout the task, and temporal generalization was used to assess whether the neural codes discriminating between the tasks during the pre-encoding phase would recur during later task periods. The spatial versus non-spatial tasks could indeed be discriminated after the onset of the cue onwards, and decoders trained during the pre-encoding phase successfully discriminated the tasks during both sample stimulus encoding and during the delay phase. This demonstrates that task-specific neural codes are established already before the memorandum is presented and that the same patterns are reestablished during stimulus encoding and maintenance. This article is part of a Special Issue entitled SI: Auditory working memory.
工作记忆中听觉空间和非空间信息的处理已被证明依赖于不同的皮质系统。虽然先前的研究已经证明，从待记忆刺激的编码开始，空间处理与非空间处理存在差异，但在这里，我们研究了在呈现样本刺激之前是否已经可以检测到这种差异。我们分析了15名健康成年人在听觉工作记忆范式中的宽带脑磁图数据，该范式从一个视觉提示开始，该提示指示给定试验的任务相关刺激特征（侧化或音高），随后是1.5秒的预编码阶段。接下来是一个样本声音（0.2秒）、延迟阶段（0.8秒）和一个测试刺激（0.2秒），之后参与者做出匹配/不匹配的决定。训练线性判别函数以解码整个任务中的特定任务信号模式，并使用时间泛化来评估在预编码阶段区分任务的神经编码是否会在后续任务期间再次出现。从提示开始后，确实可以区分空间任务和非空间任务，并且在预编码阶段训练的解码器在样本刺激编码和延迟阶段都成功地区分了任务。这表明特定任务的神经编码在呈现记忆项目之前就已经建立，并且在刺激编码和维持期间会重新建立相同的模式。本文是名为“SI：听觉工作记忆”的特刊的一部分。
