先前的研究揭示了前额叶-顶叶网络在快速目标导向分块(RGDC)中的特定作用,将与分块相关的前额叶活动与顶叶工作记忆需求分离。然而,尚不清楚前额叶和顶叶皮质如何协作完成RGDC。为此,使用了一种新颖的实验设计,在分块任务中呈现汉字,测试18名本科生(9名女生,平均年龄=22.4岁),同时记录脑电图(EEG)。在实验中,激进级分块以严格的方式及时完成(RT=1485毫秒,SD=371ms),而中风级分块的一致性较低(RT=3278ms,SD=1083ms)。通过比较激进级分块与冲程级分块,我们能够在分析的时间窗口内(-200至1300ms)在自由基级分块条件下分离分块过程。分块过程导致顶骨和枕骨皮质的伽马带同步早期增加,其次是在额叶区域的β-γ波段(25-38Hz)的功率增强。我们建议,伽马带中的后验节律活动可能是与分块的感知操作直接相关的过程的基础,虽然随后在额叶区域的β-γ激活似乎反映了一个后评估过程,例如对替代解决方案的选定规则的强化,这可能是目标导向分块的一个重要特征。
Previous studies have revealed a specific role of the prefrontal-parietal network in rapid goal-directed chunking (RGDC), which dissociates prefrontal activity related to chunking from parietal working memory demands. However, it remains unknown how the prefrontal and parietal cortices collaborate to accomplish RGDC. To this end, a novel experimental design was used that presented Chinese characters in a chunking task, testing eighteen undergraduate students (9 females, mean age = 22.4 years) while recoding the electroencephalogram (EEG). In the experiment, radical-level chunking was accomplished in a timely stringent way (RT = 1485 ms, SD = 371 ms), whereas the stroke-level chunking was accomplished less coherently (RT = 3278 ms, SD = 1083 ms). By comparing the differences between radical-level chunking vs. stroke-level chunking, we were able to dissociate the chunking processes in the radical-level chunking condition within the analyzed time window (-200 to 1300 ms). The chunking processes resulted in an early increase of gamma band synchronization over parietal and occipital cortices, followed by enhanced power in the beta-gamma band (25-38 Hz) over frontal areas. We suggest that the posterior rhythmic activities in the gamma band may underlie the processes that are directly associated with perceptual manipulations of chunking, while the subsequent beta-gamma activation over frontal areas appears to reflect a post-evaluation process such as reinforcement of the selected rules over alternative solutions, which may be an important characteristic of goal-directed chunking.