Fig. 6: The role stimulation variability in driving variability of upper-limb movements.

a Location of stimulation, via microwire array to M1 for identification of regions eliciting forelimb movement. b Patterns of stimulation delivery, with balance of total charge delivered. Patterned burst stimulation (top, PB) consisted of 333 Hz triplets, at 10 Hz triplet frequency. Random pulse stimulation (bottom, RP) consisted of single pulses, randomly timed at 30 Hz. Stimulation was delivered for 1 s per session, for a total of 30 pulses per session. c Stimulation pulse parameters, with 200 μA biphasic pulse, 200 μs per phase with 100 μs inter-phase interval. d Lateral view of paw: limb markers labeled for supervised kinematic tracking: tip of digit 4 (D4, blue), tip of digit 3 (D3, purple), and center of paw (center, black). Endpoint location of each trial (Δx, Δy) was calculated relative to start location in trial window and normalized by animal across stimulation conditions. e Example animal histograms of normalized Δx (top) and Δy (bottom) for center of paw across patterned burst stimulation trials (left) and random pulse stimulation trials (right). Gray boxes show an example 300 ms window with identical number of pulses. Kolmogorov-Smirnov test for two samples in this example animal, center of paw, p = 1.8e−11; *<0.05; **<0.01; ***<0.001, Kolmogorov-Smirnov test for two samples. Source data are provided as a Source Data file.