Meeting Abstract

79.2  Friday, Jan. 6  How do animals with limited distal limb musculature use sensory feedback during locomotion? LIEDTKE, A.M.*; MOORE, S.; WITTE, T.; SPENCE, A.J.; The Royal Veterinary College, UoL; The Royal Veterinary College, UoL; The Royal Veterinary College, UoL; The Royal Veterinary College, UoL aliedtke@rvc.ac.uk

Sense organs in the muscles, joints and cutaneous tissue provide vital feedback for the control of locomotion. Digital sensory feedback is known to be important for maintaining limb posture and body support in the face of environmental perturbations. Horses provide a unique model in which we can temporarily remove sensory feedback from the distal limb, without affecting its ability to walk and trot. This can give insight into how the nervous system tunes locomotion and the aetiology of both veterinary and human diseases. We predict that animals with limited distal limb musculature, in this case the thoroughbred horse (Equus ferus caballus), will use sensory feed back to control limb touchdown position rather than axial leg actuation to control their locomotion and maintain postural stability. We hypothesise that kinematic parameters associated with limb touchdown position will show greater variation in the absence of sensory feedback. To test this, we measured the kinematics of horses with reduced levels of digital sensation. Optical motion capture was used to collect kinematic data from horses walking and trotting on a treadmill before and after an abaxial sesamoid nerve block was administered to remove digital sensation. Interestingly, preliminary results from three horses show that a lack of sensory input results in less variability in duty factor for the initially blocked forelimb (linear mixed model; n=3, P< 0.001) for both a trot and a walk. The findings suggest that sensory feedback continuously monitors and adjusts foot placement.