Population-averaged normalized firing rates (z-score, mean ± SEM) of the vocal-only neurons in each of the three experimental conditions. A, B, Vocal production. C, D, Orofacial movement (licking). E, F, Playback. The vocal-only neurons are separated into two groups, activated (A, C, E) and suppressed (B, D, F) in the vocal production condition. The shaded bars indicate the average durations of each phee call phrase (A, B, E, F) or averaged duration of the licking (C, D).