Figure 4. Evoked EPSCs in ETd-PG cells require activation of CCK-expressing TCs. A, Example EPSCs evoked by OSN stimulation in a PG cell. Each panel contains five overlaid trials. Downward arrows correspond to OSN stimulation. B, Raster plot of EPSCs from the PG cell in A. The yellow bar indicates the presence of 590 nm light to suppress CCK-expressing cells with NpHR3.0. C, EPSC count of each trial in B in the 300 ms immediately following OSN stimulation. D, Summary PSTH of EPSC frequency across all PG cells (n = 6). Red trace, control trials; yellow trace, trials with the LED on. Note: the drop in EPSC frequency right at OSN stimulation reflects obscuring of the EPSCs by the stimulus artifact; the jump in EPSC frequency that follows is consistent with the kinetics of a monosynaptic OSN-driven EPSCs in PG cells that has been reported by Shao et al. (2009). E, Summary data of evoked EPSC frequency in the 10–300 ms window following ON stimulation (control trials, 36.21 ± 3.47 Hz; vs NpHR3.0 trials, 8.46 ± 1.52 Hz; n = 6; p = 0.031, Wilcoxon signed-rank test). F, Summary of baseline EPSC frequency during control and NpHR3.0 trials (control trials, 12.93 ± 4.57 Hz; vs NpHR3.0 trials, 17.31 ± 5.08 Hz; p = 0.094, Wilcoxon signed-rank test). G, Top, Evoked spikes recorded in an MC under control conditions and during TC inactivation. Bottom, Example excitatory currents recorded from the same MC. TC inactivation reduced the size of the current. H, Excitatory current area measurements from three MCs on interleaved trials of TC inactivation with NpHR3.0. The dashed line represents the MC in G. I, Summary data of effects on TC inactivation on OSN-evoked excitatory currents measured in MCs. * denotes p < 0.05, n.s. not significant.