Similar baseline properties of the striatonigral IPSCs in Pitx3WT and Pitx3Null mice. A1–A4: example traces of striatonigral IPSCs evoked by dorsal striatum stimulation by a train of 10 pulses at 10 Hz, 20 Hz, 50 Hz and 100 Hz, respectively, in an SNr GABA neuron in a Pitx3WT mouse. B1–B4: example traces of striatonigral IPSCs evoked by focal dorsal striatum stimulation by a train of 10 pulses at 10 Hz, 20 Hz, 50 Hz and 100 Hz, respectively, in an SNr GABA neuron in a Pitx3Null mouse. C1–C4: pooled data showing similar ratios of peak currents to the first peak current (Pn/P1) evoked by focal dorsal striatum stimulation by a train of 10 pulses at 10 Hz, 20 Hz, 50 Hz and 100 Hz in Pitx3WT and Pitx3Null mice. D: pooled data showing activity-dependent facilitation of striatonigral IPSCs in Pitx3WT mice. E: pooled data showing activity-dependent facilitation of striatonigral IPSCs in Pitx3Null mice. *P < 0.01.