Extended Data Figure 5: 20–40-Hz oscillations in dCA1 and pCA1 are functionally decoupled.

a, Time-resolved power spectra averaged across all tetrodes in the distal one-third of CA1 (dCA1, top) as well as the proximal one-third (pCA1, bottom) (9 and 14 recording sites, respectively). Data were pooled over 5 rats with hyperdrive implants spanning a wide transverse range of CA1. To control for impedance differences between tetrodes, LFP power during cue sampling was normalized, for each tetrode, to power during the pre-cue period when the animal was stationary at the odour port before the cue was delivered. Normalized power was averaged across tetrodes. Time t = 0 indicates cue onset. b, Positions of all tetrodes from which data were recorded in a, plotted in a 3D reconstruction of the CA1 cell layer. Distance from the anterior tip of subiculum is shown in micrometres. Position on the distal–proximal (DP) axis (0, distal; 1, proximal; see Supplementary Methods) was calculated in 3D space for each tetrode. CA1 tetrodes were grouped into distal (red point), intermediate (green point) and proximal (blue point) groups, each corresponding to one-third of the DP axis. c, Power spectra of LFP averaged over tetrodes in distal and proximal one-thirds of CA1 during cue sampling. Power is shown as percentage change from the pre-cue level. During cue sampling, power in the lower part of the 20–40-Hz band was stronger in dCA1 than pCA1 (11–25 Hz, green dots; q < 0.05; false discovery rate (FDR) corrected for 60 multiple comparisons at 1–60 Hz using 1 Hz bins, q < 0.05), whereas power in the higher part was lower in dCA1 (33–47 Hz, green dots; q < 0.05). d, To compare power in the lower and higher parts of the 20–40-Hz oscillation across the DP axis in CA1, the ratio of power in the slower part (20–25 Hz) and the faster part (33–40 Hz) was plotted as a function of DP distance. Each dot refers to one tetrode. Red, distal one-third; green, intermediate; blue, proximal one-third. Low/high power ratio was negatively correlated with DP distance (r(38) = −0.50, P < 0.001). e, Time-resolved coherence spectrum for dCA1 versus pCA1. Data were averaged over 28 recording pairs in dCA1 and pCA1 from animals with tetrodes in both regions. f, Mean coherence between dCA1 and pCA1. Note lack of change in 20–40-Hz coherence during cue sampling compared to pre-cue or run periods (repeated measures ANOVA, F(2, 54) = 0.75, P = 0.48).