Work

Flexible Use of Limited Resources for Sequence Working Memory in Macaque Prefrontal Cortex

Year: 2025

Type: article

Abstract: Our brain is remarkably limited in how many items it can hold simultaneously, but it can also represent unbounded novel items through generalization. How the brain rationally uses limited resources in working memory (WM) remains unexplored. We investigated mechanisms of WM resource allocation using calcium imaging and electrophysiological recording in the prefrontal cortex of monkeys performing sequence WM (SWM) tasks. We found that changes in the neural representation of SWM, including geometry, generalizable and separate rank subspaces, reflected WM load. SWM resources, represented by neurons’ signal strength and spatial tuning projected onto each rank subspace, were shared flexibly between ranks. Crucially, the prefrontal cortex dynamically utilized shared tuning neurons to ensure generalization, while engaging disjoint and spatially shifted neurons to minimize interference, thus achieving a trade-off between behavioral and neural costs within capacity. The allocated resources can predict monkeys’ behavior. Thus, the geometry of compositionality underlies the flexible use of limited resources in SWM. How the brain represents and allocates limited working memory resources remains unclear. Here the authors show that the geometry of compositionality in macaque prefrontal neurons underlies the flexible and rational use of limited resources in sequence working memory.

Source: Nature Communications

DOI: 10.1038/s41467-025-65380-0

Authors: Siwei Li, Jingwen Chen, Cong Zhang, Shiming Tang, Yang Xie, Liping Wang