Figure 8. Ripple-associated Vm depolarization and AP output are increased following induction.

a, Extracellular ripple (LFP filtered between 100 and 250 Hz) and intracellular Vm recording before (top) and after (bottom) place field induction in a CA1 pyramidal neuron. Shown is a time period during which the animal was stationary. Arrowheads indicate ripples that were detected by our algorithm (see Material & Methods). b, Enlarged view of 10 consecutive ripples and corresponding Vm. Note the increased Vm depolarization and the increased AP probability during ripples after place field induction. c, Relationships between the ripple-associated subthreshold Vm changes (ΔVm) and the locations of the ripple relative to the place field center (at 0) before (black open circles) and after (grey filled circles) place field formation. Data is taken from the cell shown in a. Each circle represents one ripple (pre: N=230 ripples, post: N=340 ripples); the lines show the linear fits. Ripple locations before and after the place field center were pooled together. d, Number of APs per ripple for events inside and outside the neuron’s place field. (mean±SEM, N=16 neurons, two-tailed unpaired t-test, pre vs post p=4.0e⁻⁴, post-inside vs-post-outside p=0.017). e, ΔVm for ripples inside and outside the neuron’s place field (mean±SEM, N=16 neurons, unpaired two-tailed t-test, pre vs post p=1.0e⁻⁴).