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Sketchpad Series

Neural signatures of coding and storing time in working memory

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Yunyun SHEN¹ (yunyunshen77@gmail.com), Sophie K. Herbst¹, Virginie van Wassenhove¹; ¹CEA, DRF/Joliot, NeuroSpin; INSERM, Cognitive Neuroimaging Unit; CNRS; Université Paris-Saclay, F-91191 Gif/Yvette, France.

Working memory (WM) critically relies on temporal processing for the order and duration of cognitive information. However, the neural mechanisms underlying the representation and the maintenance of time intervals in WM remain largely unresolved. Previous work using a novel n-item delayed duration reproduction task suggested that durations can be stored as abstract items in WM (Herbst et al., 2023). Herein, participants were presented with duration sequences consisting of either one or three temporal intervals (items), marked by brief tones. After a retention period, participants reproduced these item(s). We used this protocol with magnetoencephalography and contrasted brain activity as a function of the number of item(s) and their durations. First, we observed that during the encoding of the temporal sequence, the amplitude of the evoked response to the last tone increased with a smaller number of items and longer sequence duration. Similarly, for a single item of short duration, this amplitude correlated with the length of participants’ reproduction. Second, we examined how WM load modulated oscillatory power during the retention interval. Our preliminary observations suggest that alpha (8-12 Hz) and beta (14-30 Hz) power are modulated by the number of items and the sequence duration. Overall, as for other WM content, our findings suggest that evoked responses and oscillatory power serve as neural signatures of temporal information encoding and maintenance, respectively. We expect that this study will help further clarify the representation of duration in WM.

Topic Area: EXECUTIVE PROCESSES: Working memory