Fig. 6.
Nonphase-precessing interneuron. (A) Firing rates of two pyramidal cells (red, P1; magenta, P2) and an interneuron (black, IN) as a function of distance on the running track. (B) The spikes of the interneuron are locked to a small phase range (compare Fig. 4). The circular mean phases of the two simultaneously recorded pyramidal cells are marked with red dots and magenta stars, respectively. (C) Temporal cross-correlograms between P1 and interneuron IN and P2 and the same interneuron IN. Note that both pyramidal cells are anticorrelated to the activity on the interneuron. The dashed lines give the 95% C.I. for phase locking; cross-correlograms exceeding this C.I. have a significant correlation beyond phase locking. (D) Autocorrelogram, θ-spike cross-correlogram, and ripple–spike cross-correlogram of the interneuron.