Calculating the synaptic conductance generated by a GPe neuron on its SNr target cell. A, Firing of a prototypic GPe neuron in the absence of any stimulus. B, Convolution of the spike times of the cell in A, using the average conductance waveform for the pallido-nigral synapse (from Simmons et al., 2020). C, Synaptic depression at the pallido-nigral synapse using the measurements by Connelly et al. (2010). D, Synaptic conductance produced by the spike train in A, depressing to a steady state. E, The amplitude of the steady-state IPSG peaks as a function of firing rate. F, The time-average synaptic conductance at steady state for a single GPe neuron’s synapse on a postsynaptic SNr neuron as a function of firing rate. At rates >20 spikes/s, changes in firing rate produce little change in average inhibitory conductance. G, Synaptic conductance waveform calculated from the response of an example GPe neuron during stimulation with a 2 Hz 20 pA sine wave current, calculated without synaptic depression or stochastic fluctuations in synaptic current. Red represents the sine wave current. H, Synaptic conductance waveform calculated for the same neuron and same stimulus, but including synaptic depression. I, Synaptic conductance waveform calculated for the same neuron and stimulus, including the effect of synaptic depression and stochastic fluctuations in IPSG amplitude.