Number of calls emitted in playback categories included in the statistical analysis.

PreUS-NS and PreBKG-NS are the No Stimulus blocks preceding the Ultrasonic and Background noise blocks, respectively. Bold values are the number of calls emitted during NS periods following US or AUD blocks; this calling activity may result from the post-stimulus excitatory state of the frog. The difference in the average number of calls produced during the blocks is statistically significant (P = .008), and the number of calls emitted during the US stimulus periods is significantly higher than the average number produced during the PreBKG-NS blocks (Wilcoxon Signed Ranks, P = .043).