Working memory (WM) is constructive in nature. Instead of passively retaining information, WM reorganizes complex sequences into hierarchically embedded chunks to overcome capacity limits and facilitate flexible behaviour. Here, to investigate the neural mechanisms underlying hierarchical reorganization in WM, we performed two electroencephalography and one magnetoencephalography experiments, wherein humans retain in WM a temporal sequence of items, that is, syllables, which are organized into chunks, that is, multisyllabic words. We demonstrate that the one-dimensional sequence is represented by two-dimensional neural representational geometry in WM arising from left prefrontal and temporoparietal regions, with separate dimensions encoding item position within a chunk and chunk position in the sequence. Critically, this two-dimensional geometry is observed consistently in different experimental settings, even during tasks not encouraging hierarchical reorganization in WM and correlates with WM behaviour. Overall, these findings strongly support that complex sequences are reorganized into factorized multidimensional neural representational geometry in WM, which also speaks to general structure-based organizational principles given WM’s involvement in many cognitive functions.

工作记忆 （WM） 本质上是建设性的。WM 不是被动地保留信息，而是将复杂的序列重新组织成分层嵌入的块，以克服容量限制并促进灵活的行为。在这里，为了研究 WM 中层次结构重组的神经机制，我们进行了两次脑电图和一次脑磁图实验，其中人类在 WM 中保留了项目的时间序列，即音节，这些项目被组织成块，即多音节词。我们证明，一维序列由来自左前额叶和颞顶叶区域的 WM 中的二维神经表示几何表示，具有单独的维度编码块内的项目位置和序列中的块位置。至关重要的是，这种二维几何结构在不同的实验环境中始终如一地观察到，即使在不鼓励 WM 中分层重组的任务中也是如此，并且与 WM 行为相关。总体而言，这些发现强烈支持在 WM 中将复杂序列重组为分解的多维神经表示几何，这也说明了鉴于 WM 参与许多认知功能，这也说明了基于结构的一般组织原则。