Extended Data Figure 3: Power and coherence over a broader spectrum of frequencies in dCA1 and LEC at the end of training.
From: Coordination of entorhinal–hippocampal ensemble activity during associative learning
a–d, Time-resolved power spectra averaged across tetrodes in a, dCA1 (n = 9 tetrodes), b, pCA1 (n = 14 tetrodes), c, LEC (n = 10 tetrodes) and d, MEC (n = 8 tetrodes), as in Fig. 1e and g, but for a broader band of the frequency spectrum (0–140 Hz). Power is shown as percentage change from power during the pre-cue period. dCA1 and pCA1 data are from the same animals (rats with tetrodes along the entire proximodistal CA1 axis), whereas LEC and MEC data are from separate animals (5 and 4 rats, respectively). Right panels show mean power for frequencies up to 140 Hz during cue sampling (red) and during running from cue port to food cups (blue). Peak frequencies are indicated. In CA1, the mean power in the 20–40-Hz frequency band increased from (1.07 ± 0.04) × 10−3 before cue sampling to (1.36 ± 0.05) × 10−3 during cue sampling and then reverted to (0.89 ± 0.05) × 10−3 mV2 after cue sampling (repeated measures ANOVA: F(2, 78) = 118, P < 0.001). In LEC, the power was (1.05 ± 0.12) × 10−3, (1.62 ± 0.16) × 10−3 and (0.78 ± 0.08) × 10−3 mV2, respectively (F(2, 18) = 67.1, P < 0.001). e, f, Time-resolved coherence spectra averaged across tetrode pairs in LEC and dCA1 (e) and in MEC and dCA1 (f), as shown in Fig. 1h, but across a broader band of the frequency spectrum (same animals as in c and d; data are averaged across all EC-dCA1 tetrode pairs). Note that, during running, MEC shows fast gamma oscillations (60–100 Hz) that are coherent with dCA1 LFPs (arrows). Right panels show mean coherence spectra during cue sampling (red) and during running (blue), with peak frequencies indicated. LEC did not show fast gamma oscillations.
