Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK.
Department of Experimental Psychology, University of Oxford, Oxford, UK.
Cereb Cortex. 2018 Oct 1;28(10):3685-3696. doi: 10.1093/cercor/bhy167.
A frequently repeated finding is that the default mode network (DMN) shows activation decreases during externally focused tasks. This finding has led to an emphasis in DMN research on internally focused self-relevant thought processes. A recent study, in contrast, implicates the DMN in substantial externally focused task switches. Using functional magnetic resonance imaging, we scanned 24 participants performing a task switch experiment. Whilst replicating previous DMN task switch effects, we also found large DMN increases for brief rests as well as task restarts after rest. Our findings are difficult to explain using theories strictly linked to internal or self-directed cognition. In line with principal results from the literature, we suggest that the DMN encodes scene, episode or context, by integrating spatial, self-referential, and temporal information. Context representations are strong at rest, but rereference to context also occurs at major cognitive transitions.
一个经常被重复的发现是，默认模式网络（DMN）在外部关注任务中显示出激活减少。这一发现导致 DMN 研究强调内部关注自我相关的思维过程。相比之下，最近的一项研究表明，DMN 与大量的外部关注任务转换有关。使用功能磁共振成像，我们扫描了 24 名参与者进行任务转换实验。在复制先前的 DMN 任务转换效应的同时，我们还发现短暂休息以及休息后任务重新启动时 DMN 会有较大的增加。我们的发现很难用严格与内部或自我导向认知相关的理论来解释。与文献中的主要结果一致，我们认为 DMN 通过整合空间、自我参照和时间信息来编码场景、情节或上下文。上下文表示在休息时很强，但在主要认知转换时也会重新参考上下文。
