Onishi Hayate, Yokosawa Koichi
Graduate School of Health Sciences, Hokkaido University, Sapporo, Japan.
Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
Front Hum Neurosci. 2023 Aug 23;17:1218437. doi: 10.3389/fnhum.2023.1218437. eCollection 2023.
Previous studies have reported that, in working memory, the processing of visuospatial information and phonological information have different neural bases. However, in these studies, memory items were presented via different modalities. Therefore, the modality in which the memory items were presented and the strategy for memorizing them were not rigorously distinguished. In the present study, we explored the neural basis of two working memory strategies. Nineteen right-handed young adults memorized seven sequential directions presented visually in a task in which the memory strategy was either visuospatial or phonological (visuospatial/phonological condition). Source amplitudes of theta-band (5-7 Hz) rhythm were estimated from magnetoencephalography during the maintenance period and further analyzed using cluster-based permutation tests. Behavioral results revealed that the accuracy rates showed no significant differences between conditions, while the reaction time in the phonological condition was significantly longer than that in the visuospatial condition. Theta activity in the phonological condition was significantly greater than that in the visuospatial condition, and the cluster in spatio-temporal matrix with < 5% difference extended to right prefrontal regions in the early maintenance period and right occipito-parietal regions in the late maintenance period. The theta activity results did not indicate strategy-specific neural bases but did reveal the dynamics of executive function required for phonological processing. The functions seemed to move from attention control and inhibition control in the prefrontal region to inhibition of irrelevant information in the occipito-parietal region.
以往的研究报告称，在工作记忆中，视觉空间信息和语音信息的处理具有不同的神经基础。然而，在这些研究中，记忆项目是通过不同的模态呈现的。因此，记忆项目的呈现模态和记忆策略没有得到严格区分。在本研究中，我们探究了两种工作记忆策略的神经基础。19名右利手的年轻成年人在一项任务中记住了以视觉方式呈现的七个连续方向，在该任务中，记忆策略要么是视觉空间策略，要么是语音策略（视觉空间/语音条件）。在维持期，通过脑磁图估计θ波段（5 - 7赫兹）节律的源振幅，并使用基于聚类的置换检验进行进一步分析。行为结果显示，各条件下的准确率没有显著差异，而语音条件下的反应时间显著长于视觉空间条件下的反应时间。语音条件下的θ活动显著大于视觉空间条件下的θ活动，时空矩阵中差异小于5%的聚类在维持早期扩展到右前额叶区域，在维持后期扩展到右枕顶叶区域。θ活动结果并未表明特定于策略的神经基础，但确实揭示了语音处理所需执行功能的动态变化。这些功能似乎从前额叶区域的注意力控制和抑制控制转移到枕顶叶区域对无关信息的抑制。
