Working Memory Updating in the Macaque Lateral Prefrontal Cortex

Abstract

Working memory updating is an important executive process. Here, we study the single-neuron mechanisms involved in updating versus protecting memory from distractors in the macaque prefrontal cortex. We recorded single-neuron activity from the lateral prefrontal cortex (LPFC) and prearcuate cortex (PAC) while male monkeys performed a task that required them to update their memory of target locations while ignoring distractors. Our findings revealed that neurons in the PAC signaled updated memory locations ∼100 ms after stimulus onset, significantly faster than the ∼400 ms observed in the LPFC. Additionally, PAC neurons exhibited longer encoding of distractor information. Population decoding analyses further indicated that distractor information was maintained in orthogonal subspaces from target information in both regions, minimizing interference. These results demonstrate the distinct temporal dynamics in memory updating processes between the PAC and LPFC and highlight the interplay between robust memory maintenance and updating, suggesting that local neural mechanisms may contribute to these processes.

Keywords: distractor; macaque; monkey; prefrontal; updating; working memory.