The average profiles (across all sessions and animals) of different variables are calculated for the long (black) and short (red) tracks. a, Significant differences were observed for the population firing rates of pyramidal cells, which cannot be accounted for by the different running speed profiles (d, e). b, The interneuron firing rates were not systematically different. c, The spiking profiles were similar between the long and short track, with higher occupancy at the beginning of the track. d, The running speed profiles reflect a higher peak running speed in the middle of the short track. e, Firing rate is plotted against running speed for each position pixel on the track (see also supplemental Fig. S5, available at www.jneurosci.org as supplemental material). The best-fit lines are also shown. The higher firing rates on the short track cannot be explained by running speed. f, The theta-frequency increases by a small (0.6%) but significant (rank-sum, p < 10⁻²⁰) amount from the long to the short track. The local field potential theta power decreased in both CA1 (g) and CA3 (h) on the short track. i, Coherence in the theta-frequency band also decreased between the two structures (see also supplemental Fig. S7, available at www.jneurosci.org as supplemental material).