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Does a shift in mental time translate into a shift in low-frequency oscillations?

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Anna M.A. Wagelmans¹ (anna.wagelmans@cea.fr), Virginie van Wassenhove¹; ¹CEA/DRF/Inst. Joliot, NeuroSpin; INSERM, Cognitive Neuroimaging Unit; Université Paris Saclay, Gif/Yvette, France

Through mental time travel (MTT), humans can explore past events or possible futures. One hypothesis is that MTT builds on flexible temporal cognitive maps of events’ position in time (Gauthier & van Wassenhove, 2016). Previous studies showed the implication of the hippocampal-entorhinal system for MTT (Gauthier et al., 2020), where the sequential firing of neuronal assemblies on shifting phases of theta oscillations codes for spatial position and distance (Dragoi & Buzsáki, 2006). Yet, the computation of temporal distances remains to be characterized. In a novel paradigm (N = 63), participants mentally projected themselves to different dates in the past or future. They were shown historical events, and had to report whether the event would happen before or after, with respect to their temporal position. The further away in time participants imagined themselves to be, the slower their reaction times. This behavioural parametric shift shows that distance computations can be captured during MTT, grounding the hypothesis of a similar shift in neural responses. Herein, we adapted this task to magnetoencephalography (N = 31). We show that the amplitude of neural responses evoked by mentally projecting in time increased compared to being in the present, but did not shift along distance. This suggests that the evoked response captures the operation of mentally projecting oneself, but not the underlying distance computations. Analyses are ongoing to test whether the phase of low-frequency oscillations shifts with the distance of projection, which would provide evidence that temporal distance computations can be implemented by low-frequency neural dynamics.

Topic Area: LONG-TERM MEMORY: Episodic