Responses of three example vocalization-correlated neurons and three hand-correlated neurons in ‘vocal’ and ‘manual’ trials as well as averaged and normalized population responses for the corresponding examples. Responses are recorded in PMrv (left column), ASi (middle column), and VPA (right column). (A,C,E) Three example vocalization-correlated neurons that show a significant increase of neuronal activity during 450 ms before the instructed vocalization compared to baseline (450 ms before ‘go’ cue onset). At the same time, the neurons show only minor changes in activity preceding the response in ‘manual’ trials. Upper panel show the raster plot, black dots and asterisks indicate the ‘go’ cue onset in the ‘vocal’ and ‘manual’ trials, respectively. The lower panel represent the corresponding spike density histogram averaged and smoothed with a Gaussian kernel (150 ms) for illustration. The vertical black line indicates the response onset. Vocal responses have an average duration of 97 ± 40 ms. (B,D,F) Averaged and normalized activity of all vocalization correlated neurons recorded in the corresponding area. These-neurons show a significantly different activity prior to cued ‘vocal’ responses compared to cued ‘manual’ responses (activity tested in 450 ms before response onset; Mann Whitney U test: p<0.001). (G,I,K) Three example hand-correlated neurons showing a significant increase in firing rate before the instructed ‘manual’ response compared to baseline activity. The activity in ‘vocal’ trials remains at baseline level. (H,J,L) Averaged and normalized activity of all hand-movement-correlated neurons recorded in the corresponding area. Hand-correlated neurons show a significant change in firing rate only preceding ‘manual’ responses but not preceding ‘vocal’ responses (activity tested in 450 ms before response onset; Mann Whitney U test: (H,J) p<0.001, (L): p=0.115). Shaded area around the curves depicts the standard error of the mean (s.e.m.).