Figure 4.

Changes in trident whisker angle during ground acceleration. A, B, Representative trials (for slow and fast backward ground movement) in which the midline trident whisker angle (blue line) decreases as ground velocity (black line) increases. Angle denominatation: 0° was a line drawn perpendicular to the rat's fur. More negative angles correspond to more strongly deflected whisker positions; less negative angles correspond to smaller deflections. C, Sample frame from a high-speed video taken during backward ground movement at 3.5 cm/s (top) and 14 cm/s (bottom). D, Trace of midline whisker during 3.5 cm/s and 14 cm/s ground movement with respect to the origin (location where the trident whisker meets the fur), demonstrating that trident whisker defects more at slower ground velocity (black trace).