Fig. 3: BaxCKO mutants exhibit gamma rhythmopathies in the dorsal hippocampus.

a Experimental preparation. LFP signals were recorded with 16-channel linear silicon probes from the dorsal hippocampus of head-fixed mice (Mouse schema from Ann Kennedy. Mouse profile (Zenodo, 2020; doi:10.5281/zenodo.392591)). b Representative examples of LFP recordings from different layers in a control and a BaxCKO mutant. The probe position was validated (middle). SO stratus oriens, SP stratum pyramidale, SR stratum radiatum, SLM stratum lacunosum moleculare. c Boxplots showing distribution of theta and gamma power spectra recorded at SLM for controls (17 sessions from 3 mice) and BaxCKO mutants (16 sessions from 3 mice). The central mark is the median, the box edges are the 25th and 75th percentiles, and the whiskers are the data maxima and minima excluding outliers. Differences were observed in both theta (p = 0.0211, bottom left) and gamma (p = 0.04, Kruskal–Wallis test; bottom right). Red cross denotes an outlier. d Same as in c for SP. Group differences were observed for gamma power (40–80 Hz; p = 0.0055; Kruskal–Wallis test) but not for theta (p = 0.614). e Histological validation of enhanced CRs density from a given BaxCKO mouse section showing overlap of tdTomato reporter and the CR-specific P73 marker (38.33 ± 3.95 cells/mm for controls and 52.76 ± 15.66 cells/mm for mutants, p = 0.03, Kruskal–Wallis. n = 13 controls and n = 15 mutants. Data presented as mean density ± SD). f Correlations between CR density at the HF within area CA1 and theta (left) and gamma (right) power recorded at the at SP (top panels) and SLM (bottom panels). Note correlation between CR density and gamma (Pearson correlation, r = 0.39, p = 0.04; two-tailed significance test), but not theta power at SP, and theta (Pearson correlation, r = −0.44, p = 0.02; two-tailed significance test), but not gamma, power at SLM. Data from 13 control sessions from 3 mice and 15 mutant sessions from 3 mice with clear probe track identification.