Extended Data Figure 1: Mouse behavior exhibits sub-second syllable structure when keypoints are tracked from below.

a) 2D keypoints tracked using infrared video from a camera viewing the mouse through a transparent floor. b) Egocentrically aligned keypoint trajectories (bottom) and change scores derived from those keypoints (top, see Methods). Vertical dashed lines represent changepoints (peaks in the change score). c) Distribution of inter-changepoint intervals. d) Keypoint change score aligned to syllable transitions from depth MoSeq. Results in (c) and (d) are shown for the full dataset (black lines) and for each recording session (gray lines).