Fig. 4: Gross forelimb kinematics capture CFA influence worse than muscle activity.

a, Time series of tracked forelimb sites and their corresponding first derivatives surrounding inactivation and control trials windowed into overlapping segments. The segments are used to create 2D embedding via UMAP. b, Image showing the locations of the eight sites tracked on the forelimb, according to the color code in a. c, Example map of forelimb orientation states from one mouse, along with the trial-averaged positions of the forelimb sites at selected grid points within the map (red circles). As the video was captured at 100 Hz, time series segments used here had 10-ms spacing between points instead of 5 ms, as in Fig. 2. d–g, Distributions of the sizes of inactivation effects on muscles (d), P-value distributions for inactivation effects on muscles (e), distributions of the sizes of inactivation effects on four main forelimb sites (f) and P-value distributions for inactivation effects on four main forelimb sites (g), calculated using forelimb orientation maps, across all grid points and all eight mice. The error bars in e and g indicate the s.e.m. h, Histograms of Pearson’s correlation between muscle activity and four forelimb site positions (shoulder, elbow, wrist and finger), aggregated over all eight mice and all four sites. i,j, Maps of muscle activity states (left: orange) and limb orientation states (right: green) from one animal. Black circles in each panel mark corresponding sets of embedded vectors on the two maps (that is, those coming from the same set of epochs). The marked sets are clustered based on muscle activity state (i) or limb orientation state (j). Both map types used the same time point spacing (10 ms) and equivalent amounts of data. k, For the embedded vectors from 200 randomly selected epochs, the Euclidean distance between all possible pairs of those vectors on the muscle activity map in i and j plotted against the distance between their corresponding vectors on the limb orientation map. corr., correlation; ES1 and ES2, first and second sites between elbow and shoulder joints; WE1 and WE2, first and second sites between wrist and elbow joints.