Vision fine-tunes preparation for landing in the cane toad, Rhinella marina

In toad hopping, the hindlimbs generate the propulsive force for takeoff while the forelimbs resist the impact forces associated with landing. Preparing to perform a safe landing, in which impact forces are managed appropriately, likely involves the integration of multiple types of sensory feedback. In toads, vestibular and/or proprioceptive feedback are critical for coordinated landing, however, the role of vision remains unclear. To clarify this role, this study compares pre-landing forelimb muscle activation patterns in animals before and after removing vision. Specifically, we recorded EMG activity from two antagonistic forelimb muscles, the anconeus and coracoradialis, which demonstrate distance-dependent onset timing and recruitment intensity, respectively. Toads were first recorded hopping normally and then again after their optic nerves were severed to remove visual feedback. When blind, toads exhibited basic hop kinematics and pre-landing muscle activity similar to when sighted...