Figure 1.

Experimental designs. A, Tunnel setup for recording of locomotion. B, C, The side and the bottom view of a control mouse just before (B) and during (C) scratching caused by mechanical stimulation of the pinna (Stim; in B). In C, P, the amplitude of the limb protraction [excursion of the hindlimb from initial position (indicated by dotted line) to the stimulation point] that preceded rhythmic scratching movements. D, Side (top) and bottom (bottom) views of the distal point trajectory of the hindlimb (C, red line) during one scratching cycle. Time between points 10 ms. D-V, excursion of the limb in the dorsoventral direction; M-L, excursion of the limb in the mediolateral direction; and R-C, excursion of the limb in the rostrocaudal direction. Blue dashed line is the orientation of the body axis estimated from the view from below as a line connecting the mouth with the base of tail. Rostral end (R) and caudal end (C) of the body axis. E, Righting behavior. Sequential positions of the mouse (1–4) that, starting from an upside-down position, acquired a dorsal side-up position. Two stages of the righting (stage 1 and stage 2) are indicated. F, Setup for testing postural corrections. The animal performed postural corrections in response to the lateral tilts of the supporting platform. The rear view of the animal was used to measure the platform tilt (α), and the tilt of the caudal part of the trunk in relation to vertical (β) and in relation to the platform (γ). The dorsoventral trunk axis was determined as a line connecting the marker positioned on the spine at the level of the rostral pelvis (black circle) and the axis of rotation. G, Tilts of the platform (α) caused lateral displacement of the trunk in relation to the platform (γ) and to external space (β). H, Activity of the left Gast (Gast-L) and right Gast (Gast-R) recorded in control mice during postural corrections caused by the platform tilts.