title: Optimal sensorimotor transformations for balance.
abstract: Here we have identified a sensorimotor transformation that is used by a mammalian nervous system to produce a multijoint motor behavior. Using a simple biomechanical model, a delayed-feedback rule based on an optimal tradeoff between postural error and neural effort explained patterns of muscle activation in response to a sudden loss of balance in cats. Following the loss of large sensory afferents, changes in these muscle-activation patterns reflected an optimal reweighting of sensory feedback gains to minimize postural instability. Specifically, a loss of center-of-mass-acceleration information, which allowed for a rapid initial rise in the muscle activity in intact animals, was absent after large-fiber sensory neuropathy. Our results demonstrate that a simple and flexible neural feedback control strategy coordinates multiple muscles over time via a small set of extrinsic, task-level variables during complex multijoint natural movements.
authors.affiliation: Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, Georgia 30332-0535, USA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Lockhart
authors.forename: Lena H
authors.initials: LH
authors.lastname: Ting
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002415:Cats; D003198:Computer Simulation; D004576:Electromyography / Q000379:methods; D005246:Feedback; D008297:Male; D008954:Models, Biological; D009068:Movement / Q000187:drug effects / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology; D004856:Postural Balance / Q000187:drug effects / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D011736:Pyridoxine / Q000494:pharmacology; D012677:Sensation / Q000187:drug effects / Q000502:physiology*; D014803:Vitamin B Complex / Q000494:pharmacology
chemical_list: D014803:Vitamin B Complex; D011736:Pyridoxine