Effect of systemic injection of (R,S)-ketamine on bursting activity of LHb neurons. A, Schematic illustration of experimental protocol. B, Recording sites of each tetrode and example traces and average spike waveform of LHb neurons. C, Percentage of spikes in bursting and number of bursts per minute of LHb neurons from control and CRS rats. ***p < 0.001; n = 38 and 39. D, Effect of systemic administration of (R,S)-ketamine on the percentage of spikes in bursting and the number of bursts per minute of LHb neurons. **p < 0.01, ***p < 0.001, n.s., not significant. n = 20. E, Cumulative distribution of interspike intervals (ISIs). **p < 0.01, n.s., not significant.