Supplementary Figure 13: Cluster-matching to identify cells recorded across days.

(a) Examples of cells co-recorded across two days. Different colors indicate cells recorded in different animals. Shades of blue indicate cells from iWT mice and shades of red highlight cells from iCre-KO mice. The tetrode number and recording day (day 1 = D1, day 2 = D2) are indicated above scatterplots showing the relationship between peak to trough amplitudes for all signals recorded on each pair of electrodes (e) on a given tetrode (from top left to bottom right: e1 vs e2, e1 vs e3, e1 vs e4, e2 vs e3, e2 vs e4, e3 vs e4). Each dot represents a single sampled spike. Spikes associated with each isolated place cell are shown in a different color. For clarify, only clusters containing spikes emitted by place cells recorded on both D1 and D2 are shown (top panels). For each place cell, the average waveform on each channel and each day is shown (bottom right panels). Smoothed firing rate maps (bottom left panels) are color coded for maximum (red) and minimum (blue) values. Maps are shown for each day (map D1 and map D2), as well as the cross-correlation between the two maps (X-corr). (b) Histogram of cluster center-of-mass (COM) shifts for all iWT and iCre-KO place cells recorded across days (n = 25 iWT shifts, 36 iCre-KO shifts). Cluster center-of-mass shifts across days were smaller for iCre-KO cells (mean ± SD: iWT = 0.16 ± 0.067, iCre-KO = 0.11 ± 0.057, two-tailed WRS, Z = 2.49, p = 0.010), indicating that improper identification of cells across days did not lead to the decreased place stability we observed in iCre-KO mice. (c) There was not a significant relationship between the cluster center-of-mass shift and the place cell shift across days in either group (Pearson’s correlation, iWT: r (23) = −0.39, p = 0.051; iCre-KO: r(34) = 0.0075, p = 0.97; n = 25 iWT cells, 36 iCre-KO cells).