The role of ventral lateral line organs in water wave localization in the clawed toad (Xenopus laevis)

Abstract

1. The role of the ventral lateral line organs in water surface wave localization in the clawed toad,Xenopus laevis Daudin, was tested in blinded animals with various lesions of lateral line organs. 2. After destruction of all its dorsal lateral line organs, but with all its ventral organs intact,Xenopus shows normal responsiveness and full response accuracy to waves from any direction (Fig. 2). 3. Additional partial destruction of ventral organs seriously impairs wave localization (Fig. 2). Determination of the stimulus side, however, is mostly not affected by these lesions (Table 1). Thus, information about the side to which to turn, and the angle through which to turn are obtained differently from lateral line input. 4. Xenopus with only one side's dorsal receptors intact responds to waves as accurately as animals with intact dorsal and ventral receptors on that side (Fig. 2). Thus, ventral input does not improve accuracy of localization in the horizontal plane beyond that provided already by the dorsal receptors alone. 5. Xenopus with only its ventral receptors intact shows a significant increase in turning down, which is specific for this type of lesion (Table 2). Thus, comparison between dorsal and ventral inputs is involved in vertical localization. 6. InXenopus with only its ventral receptors on one head side intact, turn angles to given stimulus angles vary more than in specimens with total lateral line destruction. This suggests a hierarchy inXenopus' reliance on its sense organs for wave localization in that even indistinct lateral line input is taken as more relevant than the information from the frog's other wave localizing organ(s).