Variability of steady state depression changes as a function of activation frequency. (A) Example traces from EP neurons during stimulation of the GP at 5 Hz. The steady state depression is indicated above each recording. (B) The distribution of the steady state depression for each of the stimulation frequencies extracted from the experimental data (i), from simulated IPSPs evoked by regular stimulation (ii) and from simulated IPSPs evoked by Poisson stimulation (iii). (C) The mean and variance of the change in EP membrane potential as a function of the activation frequency. (D) The limiting frequency of GP-EP synapses as a function of the steady state depression (measured from stimulation of the GP at 10 Hz). R2 = 0.44, p = 0.049.