Figure 5.

Activity in a single pre-junctional neuron increases the excitability of a post-junctional IN. (A) Examples of APs in the pre-junctional neuron (Vpre) increasing the excitability of the post-junctional neuron (Vpost) as revealed by injection of outward currents steps in the pre-junctional (Ipre) and post-junctional neuron (Ipost). Note: (i) absence and (ii), presence of pre-junctional AP firing. Dashed box indicates of the location of the inset from the full trace. Right panels are expanded views of traces on the left, note different scale bar. (B) Pooled data showing significant effect of pre-junctional activity on post-junctional voltage (Vm; p < 0.0001, baseline −67.2 ± 0.63 mV, +Ipre −65.6 ± 0.69 mV), AP count (p < 0.0001, baseline 3.5 ± 0.48, +Ipre 3.98 ± 0.52), latency (p < 0.0001, baseline 67.9 ± 4.17 ms, +Ipre 63.8 ± 4.42 ms) and standard deviation of AP latency (p = 0.70, baseline 3.8 ± 0.31 ms, +Ipre 3.15 ± 0.33 ms). (C) Comparison of post-junctional AP firing near rheobase in presence and absence of pre-junctional activity (10 sweeps shown in each case). (D) Pooled data showing significant effect of pre-junctional activity on post-junctional AP firing including AP firing probability (p < 0.0001, baseline 42.8 ± 3.42%, +Ipre 62.1 ± 4.75%), AP firing latency (p < 0.01, baseline 19.3 ± 0.25 ms, +Ipre 18.9 ± 0.33 ms) and standard deviation of AP latency (p = 0.07, baseline 0.86 ± 0.14 ms, +Ipre 0.99 ± 0.13 ms). n = 16 for all paired comparisons. Data are presented as paired individual points. *p < 0.05.