Extended Data Fig. 1: Engram cell turnover in the model is robust to the training window used to identify engram cells, and dynamic engrams are selectively reactivated by cues of the training stimulus.

a-b, Post-encoding evolution of the engram ensemble when using the first 60 s of the training phase to identify engram cells in Fig. 1b. Means and 99% confidence intervals are shown. n = 10 trials. a, Ensemble overlap between engram cells activated during both probing and training as a fraction of training-activated engram cells (left), probing-activated engram cells (middle) and all neurons in the network (right). b, Engram cell ensemble as a fraction of all neurons. Dashed line indicates engram cell ensemble at the end of training. c-d, Post-encoding evolution of the engram ensemble when using the entire 300 s of the training phase to identify engram cells in Fig. 1b. Means and 99% confidence intervals are shown. n = 10 trials. c, Ensemble overlap between engram cells activated during both probing and training as a fraction of training-activated engram cells (left), probing-activated engram cells (middle) and all neurons in the network (right). d, Engram cell ensemble as a fraction of all neurons. Dashed line indicates engram cell ensemble at the end of training. e-h, Population activity of engram cells (that is, firing rate averaged over all engram cells) during recall after 24 h of consolidation in Fig. 1b. Population activity is shown with a temporal resolution of 10 ms without smoothing or convolution to reflect fast changes in the population response of engram cells. Note that memory recall was considered successful upon presentation of a partial cue if the firing rate of engram cells averaged over the entire cue presentation interval was above the threshold ζ^thr = 10 Hz for engram cell activation (see Methods). e, Population activity of engram cells when cues of the training stimulus were presented during recall. Cue presentation times indicated at the top where color denotes stimulus in Fig. 1c. Dashed line indicates threshold ζ^thr = 10 Hz for engram cell activation. Representative trial is shown. f, Same as e but when cues of a novel stimulus (that is, circle in Fig. 1c) were presented. g, Same as e but when cues of a novel stimulus (that is, pentagon in Fig. 1c) were presented. h, Same as e but when cues of a novel stimulus (that is, hexagon in Fig. 1c) were presented.