Reactivating and Reorganizing Activity-Silent Working Memory: Two Distinct Mechanisms Underlying Pinging the Brain

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Can Yang¹ (12339003@zju.edu.cn), Xianhui He¹, Ying Cai¹; ¹Zhejiang University

Recent studies have suggested that working memory (WM) can be maintained in an activity-silent state, where it cannot be decoded but can be reactivated by a high-contrast visual impulse (i.e., "pinging the brain"). However, the mechanism underlying pinging the brain remains unclear. The current study tested whether the ping worked through its specific context (e.g., overlapped locations between pings and stimuli) or by generally reducing brain network noise. We recorded electroencephalograph signals from 58 participants during a delayed recall task. For each trial, two orientations were presented simultaneously along the screen's horizontal or vertical midline and a pre-stimuli cue indicated the recall order. Pings were presented during the delay period and can be categorized as context-dependent or context-independent based on whether their locations overlapped with memorized items. The Mahalanobis distance was utilized to index the representation strength at each time point and the cross-temporal decoding was calculated to examine the representational dynamics. All these analyses were based on posterior voltage signals and findings were focused on the prioritized memory items. Our results revealed comparable reactivations of pings when they were context-independent, but only the reactivations after the horizontal ones became significant when pings were context-dependent. Furthermore, for the same horizontal pings, reactivations lasted longer and representations became more generalized when pings were context-dependent. Together, we confirmed two distinct mechanisms underlying pinging the brain, context-independent pings reactivated WM through noise reduction in a transient and location-invariant way, while context-dependent pings reactivated and reorganized WM in a more sustained but location-sensitive way.

Topic Area: EXECUTIVE PROCESSES: Working memory