Figure 2.

Examples of the nominal wiping reflex behavior from two frogs are shown. A, In the first frog, the initial movement, corresponding to the first velocity peak and moving in the direction of the arrow, is medial, because of fairly synchronous activity in both limb flexor muscles (IP, ST, BF) and hip extensor muscles (RI, SM). There is little activity of VE and correspondingly no final, caudally directed whisking movement. B, In the second frog, the initial movement is more rostral, because of staggered limb flexor and hip extensor muscle activity. Subsequently, there is a distinct whisking phase corresponding to the VE activity. The end of the initial movement is indicated by gray circles and lines. The midline contact point is indicated by dashed circles and lines.