Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyoku, Kyoto 615-8510, Japan; Japan Society for the Promotion of Science (JSPS), 5-3-1 Kojimachi, Chiyodaku, Tokyo 102-0083, Japan.
Neurosci Lett. 2013 Oct 25;555:79-84. doi: 10.1016/j.neulet.2013.09.010. Epub 2013 Sep 12.
The present study investigated EEG alpha activity during visual Sternberg memory tasks using two different stimulus presentation modes to elucidate how the presentation mode affected parietal alpha activity. EEGs were recorded from 10 healthy adults during the Sternberg tasks in which memory items were presented simultaneously and successively. EEG power and suppression time (ST) in the alpha band (8-13Hz) were computed for the memory maintenance and retrieval phases. The alpha activity differed according to the presentation mode during the maintenance phase but not during the retrieval phase. Results indicated that parietal alpha power recorded during the maintenance phase did not reflect the memory load alone. In contrast, ST during the retrieval phase increased with the memory load for both presentation modes, indicating a serial memory scanning process, regardless of the presentation mode. These results indicate that there was a dynamic transition in the memory process from the maintenance phase, which was sensitive to external factors, toward the retrieval phase, during which the process converged on the sequential scanning process, the Sternberg task essentially required.
本研究采用两种不同的刺激呈现模式，在视觉 Sternberg 记忆任务中研究 EEGα 活动，以阐明呈现模式如何影响顶叶α活动。在 Sternberg 任务中，10 名健康成年人记录了他们的 EEG，在该任务中，记忆项目同时和依次呈现。在记忆维持和检索阶段，计算了α频段（8-13Hz）的 EEG 功率和抑制时间（ST）。在维持阶段，根据呈现模式，α活动不同，但在检索阶段则没有。结果表明，在维持阶段记录的顶叶α功率并不能单独反映记忆负荷。相比之下，在两种呈现模式下，检索阶段的 ST 随着记忆负荷的增加而增加，这表明存在串行记忆扫描过程，与呈现模式无关。这些结果表明，记忆过程从依赖外部因素的维持阶段到依赖于顺序扫描过程的检索阶段存在动态转变，Sternberg 任务本质上需要这种顺序扫描过程。
