Figure 1.

Characteristic Features of Local Field Potentials around CA2

(A) Representative simultaneous LFP signals recorded at SP in awake head-fixed rats using multisite silicon probes. Probe tracks are identified in sections immunostained against PCP4 and CB. The limit of MF (open arrowhead) is taken as a reference for quantitative analysis.

(B) LFP recordings around CA2 obtained from urethane anesthetized rats.

(C) Representative power spectra during theta activity recorded at SP of CA2, CA3a, and CA1p under urethane (black) and in head-fixed conditions (orange).

(D) Individual spectral area of the theta band (3–12 Hz) and the gamma band (30–90 Hz) plotted as a function of electrode distance to MF. Data are from 52 recording locations from n = 30 urethane anesthetized rats and 13 recordings from n = 5 drug-free rats. Different Pearson correlations were obtained at both sides of MF for theta: R = 0.47, p = 0.0059 from −3 to 0 mm and R = 0.59, p = 0.0088 from 0 to 1 mm. Gamma power exhibited a significant negative correlation (R = −0.65, p < 0.0001).

(E) Grand average spectra of the ripple power recorded at SP (aligned by the sharp-wave peak at SR).

(F) Delay between the ripple power peak and the sharp-wave peak as a function of recording location. Note the earlier ripple peak (negative delays) at the limit with MF (arrowhead).

See also Figure S1.