Figure 3. Simulated short-term synaptic depression and facilitation of GABAergic synapses originating from GPe neurons of the indirect pathway (A and B) and Str neurons of the direct pathway (C and D) under current clamp.

For the GPe and Str simulations, the left traces (A and C) show voltage and right panels (B and D) show the pared pulse ratios (PPR) resulting from repeated synaptic stimulation at different frequencies. The amplitude of each IPSP (P_n) was normalized to the amplitude of the first evoked IPSP (P₁). For this set of simulations $I_{APP}$ was tuned to set the resting membrane of the somatic compartment at $V_S=-60.0mV$. In both compartments $E_{GABA}$ was held fixed at –70 mV. Model performance is qualitatively, and somewhat quantitatively, similar to experimental current-clamp data (Lavian and Korngreen, 2016, Figures 2, 3).