Figure 8. Indispensable role of Kv facilitation in boosting spiking fidelity of principal neurons.

(a & b) Conductance templates (Gsyn), STD-only (individual trials in grey and average trial in black, a) and STP+STD (individual trials in pink and average trial in red, b), are generated by reversing the polarity of two sets of representative recordings of Post-I_EPSC respectively evoked by the train stimulation (400 Hz) with normal or attenuated I_K-LT facilitation (bottom panels). Spikes evoked by stimulation currents (Isyn, middle panels) in the dynamic-clamp configuration by injecting the EPSC templates into the same postsynaptic neurons are shown in top panels. (c & d) APs produced by the five individual and average conductance templates for each group are summarized. Each square represents a spike. (e & f) Raster plots of APs generated by the average conductances of five repeats against stimulus time in 12 cells. (g) Time difference between the peak of the 7^th stimulation currents and that of their resulting APs during the train stimuli, termed as spike latency, is illustrated to display the prolonged spike latency without I_K-LT facilitation. (h & i) Failure rate (h) and latency (i) of spikes produced by the STD-only (black bars) or STP+STD template (red bars) are compared (n=12). The asterisks indicate statistical significance (p<0.0001 in both cases, two-tailed paired Student’s t-tests). Error bars denote ± s.e.m.