Temporal ordering of events is fundamental to both episodic experience and action planning14. However, no dedicated mechanisms may be needed for sensing time. The same cell assembly sequences that keep information about past memories and planned goals of the animal can also faithfully track the passage of time and bridge noncontiguous events59,65,93,94 (Fig. 4b). Notably, time estimation error from the theta-bound evolving cell assembly sequences does not increase proportionally to the duration of elapsed time but stays asymptotically low even after tens of seconds of delays65. The within-cycle sequences may serve as an error-correcting mechanism of time tracking65. As is the case of place cells in a maze, the compressed temporal sequences within theta cycles predict the evolution of the real time sequences of neuronal activity during the delay portion of a memory task59. This multiple-timescale mechanism may explain why each snippet of a recalled episode is experienced as if it was occurring in real time, because the temporal dynamic during recall is supported by the same mechanism as during the encoding process.
