Variability of arm movement behavior in a sequential-target task. A, Task schematic. Monkeys were trained to reach four targets that appeared sequentially on the screen, using a planar manipulandum (image adapted from Colins Rodriguez, 2021). B, Hand speed (top), spike rasters (middle), and firing rate (bottom) for an example trial. Gray and red vertical lines indicate the times of target appearance and movement onset, respectively. Highlighted segments show movement execution colored by movement direction. C, Variability of arm movement parameters for an example session: movement direction (top; radius shows the number of movements) and duration (bottom). Colored direction slices show the bins used for direction-based analyses. Colored bars for duration indicate the bins used for duration-based analyses. D, Correlation between maximum arm movement speed and distance (left) and duration and distance (right) for one example session.