(
A–D) We re-analyzed the data using the alternative, distance-based across-session cell identification routine, with a threshold distance of 5μm (See
Figure 1—figure supplement 2). Using this alternatively analyzed data, we performed the same time decoding analyses shown in
Figure 2D–H. (
A) Performance of the ordinal time decoder. The red dots indicate perfect performance, as was achieved by using data from both environments together. Sorting of the sessions using data from one of the environments significantly outperformed sorting of the sessions using data in which the day labels of each cell’s activity patterns were randomly shuffled (gray dots, n =10 shuffles per mouse). (
B) Distributions of the correlations between ensemble activity patterns averaged over the seven pairs of neighboring days for all 8!/2 possible day permutations. Vertical lines indicate the mean correlations between activity patterns of pairs of neighboring days of the actual data. As in the analysis shown in
Figure 2C and
Figure 2—figure supplement 2A, we found that in all mice, actual data yielded the highest mean correlation of all possible permutations. (
C) A ‘within-environment time decoder’ was trained and tested on data from the same environment. Shown are distributions of the decoder’s errors in inferring the day from which a test data (single trials) was taken. The decoder successfully inferred the days from which the test data was taken in the majority of cases. (
D,E) An ‘across-environment time decoder’ was trained on data from one environment (A or B) and tested on data from the other environment (B or A, respectively). Shown are distributions of the decoder’s errors in inferring the day from which a test data consisting of single sessions (
D) or single trials (
E) were taken. The decoder successfully inferred the day from which the test data was taken in the majority of cases. (
F, G) Changing the threshold for a candidate cell to register as the same neuron across sessions did not alter the conclusions regarding the performance of the across environment time decoder. (
F) The success rates of the time decoder changed only slightly and were highly significant in comparison to the chance level over a broad range of thresholds used by the correlation-based across-session cell identification routine (z-test, p < 10
-8 for all comparisons). The red data point indicates optimal threshold, consistent with an independent analysis shown in
Figure 1—figure supplement 2C. (
G) The success rates of the time decoder changed only slightly and were highly significant in comparison to the chance level over a broad range of thresholds used by the distance-based across-session cell identification routine (z-test, p < 10
-8 for all comparisons). The red data point indicates optimal threshold, consistent with an independent analysis shown in
Figure 1—figure supplement 2D. Data are mean ± s.e.m.