Extended Data Fig. 1: Characterization of free movement.

a. Mean head pitch and roll during free motion for one example recording. Pitch mean = −15.1 ± 0.02 deg; Roll mean = 9.2 ± 0.01 deg. b. Mean head pitch and roll, indicating the center point during free movement. Each point is a mouse (n = 9 mice). Black bars indicate mean and standard error (pitch: −20.8 ± 3.1 deg; roll: 4.5 ± 3.3 deg). Recording from a shown in orange. c. Rate of gaze-shifting (left; run median = 106 ± 6 saccades/min; still median = 50 ± 3 saccades/min) and compensatory (right; run median = 362 ± 11 saccades/min; still median = 229 ± 15 saccades/min) movements during periods of locomotion greater than 2 cm/s measured from the top camera (‘run’) compared to periods of slower locomotion, fine motion, and/or stationary periods less than 2 cm/s (‘still’). Each point is a mouse (n = 9 mice). Black bars indicate median and standard error. d. Amplitude of position change for eye (left), head (middle) and gaze (right; defined as eye + head) during gaze-shifting and compensatory eye/head movements at the onset of the movement for the example recording used in a. e. Scatter plot of eye and head velocities subsampled (25x) from the example recording used in a, showing compensatory, gaze-shifting, and intermediate movements, the latter of which are excluded from the analysis in the main text. f. Amplitude of gaze changes at onset of movement for the example recording used in a. g. Median ± SEM amplitude of gaze change for all recordings. Each recording is a point (n = 9 mice). Recording in f is shown in orange. Compensatory: 0.73 ± 0.02 deg; intermediate: 2.63 ± 0.01 deg; gaze-shifting: 8.76 ± 0.29 deg. h. PETHs for example cells from Fig. 1g including PETH for responses to intermediate saccades in black. i. Normalized PETHs of gaze-shifting (left), intermediate (middle), and compensatory (right) eye/head movements for 100 example units with a baseline firing rate >2 Hz, with median of all cells (n = 716) overlaid.