(a) Depth profiles of the electrophysiological signals recorded in the dorsal hippocampus (32 recordings, sites spaced every 100 μm) evoked by an electric pulse stimulating the perforant pathway (left panel) or during resting activity (right panel). Black traces represent the LFPs and color maps the corresponding CSD. Evoked activity was used to consistently localize the electrodes during implantation. Or, stratum oriens; pyr, pyramidal layer; rad, stratum radiatum; lm, stratum lacunosum-moleculare; gc, granule cell layer; hil, hilus. (b and c) Examples of voltage- and CSD-loadings of the three pathway-specific LFPs extracted with the ICA, with maximum loadings overlapping the corresponding afferent layers in the str. radiatum (Sch-IC), lacunosum-moleculare (lm-IC) and the molecular layer of the dentate gyrus (PP-IC). (d) Position of the recording electrode (arrows) in one representative animal. The histological section is immunostained with GFAP antibodies. (e) The power spectra of the three IC-LFPs averaged across subjects show a clear peak at the theta frequency and a broadband gamma activity. (f) Distribution of gamma amplitude (mean ± s.e.m.) in IC-LFPs along the theta cycles of the LFP recorded in pyr CA1, where its trough and peak coincide with 0 and π radians, respectively. Black waves are an example of the theta oscillation. Color coded bars represent statistically significant values relative to the surrogate distribution in all animals (Materials and methods). (g) On the left panel, we plot the results of the coherence analysis comparing the IC-LFPs against the LFP recorded in pyr CA1. Black lines represent the statistical threshold. On the right panel, the coherence analysis between IC-LFPs (green lines) is compared to the coherence between raw LFP channels recorded at the layers with maximum contribution to each IC-LFP (dashed lines, **p<0.01, we used a two-way ANOVA to compare the theta coherence between pairs of IC-LFPs versus theta coherence between raw LFPs, followed by Bonferroni correction, F(1,12)=32.01, N = 5). (h) Theta phase difference between IC-LFPs and LFPs recorded in CA1 pyr layer. Gray lines represent individual theta wave’s phase relative to CA1 pyr theta trough (at 0/2π radians). Average phase is represented by the colored thick line. Length of the thick line represents ICPC.