Sensory feedback and coordinating asymmetrical landing in toads

Area of Science:

• Animal Behavior
• Neuroscience
• Biomechanics

Background:

• Coordinated landings in animals depend on sensory input to predict impact timing and magnitude.
• Cane toads are known for their ability to perform coordinated landings during locomotion.
• Understanding sensory prioritization is key to comprehending motor control during dynamic movements.

Purpose of the Study:

• To investigate how cane toads prioritize visual versus vestibular feedback during hopping.
• To determine the role of different sensory modalities in predicting and executing asymmetrical landings.

Main Methods:

• Recorded forelimb joint angles and electromyographic data from cane toads hopping.
• Induced landing asymmetry using two conditions: mid-air rolling (unstable takeoff) and sloped landing surfaces.
• Analyzed pre-landing muscle activity and movement patterns in relation to sensory information availability.

Main Results:

• When all sensory inputs (visual, vestibular, proprioceptive) could predict asymmetry (rolling condition), forelimb preparation showed asymmetry.
• When only visual feedback could predict asymmetry (sloped landing condition), no such forelimb preparation asymmetry was observed.
• Muscle activity and movement initiation were earlier in the first-landing limb when all senses were reliable.

Conclusions:

• Cane toads appear to prioritize vestibular or proprioceptive information over visual feedback for coordinating landings.
• This sensory prioritization allows for robust motor control even when visual cues are conflicting or unreliable.
• The findings shed light on the neural mechanisms underlying sensorimotor integration in amphibians.