Extended Data Figure 2. Selective stimulation of MSNs produces changes in peak velocity.

A) Density plot of movement trajectories showing the percentage of movements that passed through a given amplitude throughout time, aligned to movement onset. Particularly in the zoomed-in plot on the right, we can see that very few movement trajectories passed near the central 0.2 cm within the first 100ms. B) Peak velocity distributions for sham and stimulation datasets for dMSN stimulation (blue, left column), and iMSN stimulation (red, middle column). Top row shows complete distributions across animals - note that no particular part of the distribution is pronounced following stimulation. Bottom row shows means for all experimental sessions by animal. Animal number is for indexing purposes only. Most experiments were carried out concurrently across animals. The right column shows the contrast ratio (difference divided by sum) for dMSN and iMSN stimulation effects (blue and red respectively). These data show a steady mean shift in the data; for instance, iMSN stimulation (red) is positive for velocities slower than the sham (control) mean (an increase in frequency), and is negative for velocity values greater than the sham mean (a decrease in frequency). We have curtailed the contrast ratio plot where too few values existed to achieve reliable estimates (55cm/s). C) Autocorrelation of movement velocities for dMSN stim (blue), iMSN (red), and sham (black) data. D-E exhibit the same analyses as B-C, but for those sessions in which stimulation occurred on the slower, lower 1/3 of movement velocities.