Meeting Abstract

P3.135  Monday, Jan. 6 15:30  Guinea fowl running in rough terrain with reduced proprioceptive feedback GORDON, J.C.*; DALEY, M.A.; CARR, J.; HOLT, N.C.; BIEWENER, A.A.; Royal Veterinary College, UK; Royal Veterinary College, UK; Harvard University, Cambridge, MA; Harvard University, Cambridge, MA; Harvard University, Cambridge, MA jcgordon@rvc.ac.uk

A fuller understanding of neuromuscular control of stable bipedal locomotion over rough terrain would progress many disciplines including biorobotic control. Bipedal birds such as the guinea fowl routinely negotiate complex terrain and serve as a useful animal model for integrative neuromechanics. To investigate the role of proprioceptive feedback in neuromuscular control of locomotion, we used bilateral surgical denervation, followed by re-innervation, of the lateral gastrocnemius in eight guinea fowl. This technique leads to recovery of motor output with absence of autogenic proprioceptive feedback in the gastrocnemius. Following re-innervation, we examined locomotor stability in the face of unexpected drop and obstacle perturbations, using external measures of body and limb dynamics (forces and kinematics). We then implanted tendon buckles, sonomicrometry and indwelling EMG to directly measure in vivo gastrocnemius neuromuscular function. Removal of proprioceptive feedback in a major distal limb extensor is expected to reduce dynamic stability in response to terrain perturbations. This should manifest as reduced myoelectric variability in distal limb EMG activation alongside greater variation in limb and body mechanics in the steps immediately following a perturbation. However, considering the potential speed-dependent nature of stabilizing strategies and higher reliance on intrinsic stability at high speed, reduced proprioception might influence slow movement (walking) to a greater extent than fast movement (running).