Fig 1. Tasks.

A. SCT. The trial started when the monkey placed his hand on a lever for a variable delay. Then, a visual metronome was presented, and the monkey tapped on a button to produce three intervals of a specific duration following the isochronous stimuli (synchronization phase), after which the animal had to maintain the tapping rate to produce three additional intervals without the metronome (continuation phase). Correct trials were rewarded with an amount of juice that was proportional to the trial length. The instructed target intervals were 450, 550, 650, 850, and 1,000 ms. B. ST. Similar to the synchronization phase of the SCT, the animal had to produce five intervals guided by a visual metronome. The instructed intervals were 450, 550, 650, 750, 850, and 950 ms. C. SRTT. As in ST, the trial started when the monkey placed its hand on a lever for a variable delay. However, in this task, the monkey tapped the button after six stimuli separated by a random interstimulus interval, precluding the temporalization of the tapping behavior. D. Constant error (mean ± SD/2) as a function of target interval during the SC (orange) and CC (red) of the SCT (ANOVA main effect interval, F(4, 1,112) = 61.01, p < 0.0001; main effect task condition, F(1, 1,112) = 43.16, p < 0.0001; interval × condition interaction, F(4, 1,112) = 17.66, p < 0.0001), and the ST (purple) as a function of target interval (ANOVA for 450, 550, 650, and 850 target intervals between SC of the SCT and the ST, main effect interval, F(3, 631) = 4.18, p < 0.01; main effect condition, F(1, 631) = 202.16, p < 0.0001; nonsignificant interval × condition interaction, F(3, 631) = 2.46, p = 0.06). Underlying data are available in https://doid.gin.g-node.org/d315b3db0cee15869b3d9ed164f88cfa/. CC, continuation condition; SC, synchronization condition; SCT, synchronization-continuation task; SRTT, serial reaction time task; ST, synchronization task.