title: Feed-Forwardness of Spinal Networks in Posture and Locomotion.
abstract: We present a new perspective on the concept of feed-forward compared to feedback mechanisms for motor control. We propose that conceptually all sensory information in real time provided to the brain and spinal cord can be viewed as a feed-forward phenomenon. We also propose that the spinal cord continually adapts to a broad array of ongoing sensory information that is used to adjust the probability of making timely and predictable decisions of selected networks that will execute a given response. One interpretation of the term feedback historically entails responses with short delays. We propose that feed-forward mechanisms, however, range in timeframes of milliseconds to an evolutionary perspective, that is, "evolutionary learning." Continuously adapting events enable a high level of automaticity within the sensorimotor networks that mediate "planned" motor tasks. We emphasize that either a very small or a very large proportion of motor responses can be under some level of conscious vs automatic control. Furthermore, we make a case that a major component of automaticity of the neural control of movement in vertebrates is located within spinal cord networks. Even without brain input, the spinal cord routinely uses feed-forward processing of sensory information, particularly proprioceptive and cutaneous, to continuously make fundamental decisions that define motor responses. In effect, these spinal networks may be largely responsible for executing coordinated sensorimotor tasks, even those under normal "conscious" control.
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|2 Pavlov Institute of Physiology, St. Petersburg, Russia.|3 Russian Federation State Scientific Center, Institute for Bio-Medical Problems, Russian Academy of Sciences, Moscow, Russia.|4 Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia.
authors.forename: Yury
authors.initials: Y
authors.lastname: Gerasimenko
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: Dimitry
authors.initials: D
authors.lastname: Sayenko
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: Parag
authors.initials: P
authors.lastname: Gad
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: Chao-Tuan
authors.initials: CT
authors.lastname: Liu
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|5 Brain Research Institute, University of California, Los Angeles, CA, USA.
authors.forename: Niranjala J K
authors.initials: NJK
authors.lastname: Tillakaratne
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|5 Brain Research Institute, University of California, Los Angeles, CA, USA.
authors.forename: Roland R
authors.initials: RR
authors.lastname: Roy
authors.affiliation: 2 Pavlov Institute of Physiology, St. Petersburg, Russia.
authors.forename: Inessa
authors.initials: I
authors.lastname: Kozlovskaya
authors.affiliation: 1 Department of Integrative Biology and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|5 Brain Research Institute, University of California, Los Angeles, CA, USA.|6 Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|7 Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.|8 Institute Guttmann. Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: V Reggie
authors.initials: VR
authors.lastname: Edgerton
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001921:Brain / Q000502:physiology; D025461:Feedback, Physiological / Q000502:physiology*; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*
keywords: central pattern generation; feed-forward control; spinal automaticity; spinal cord injury; spinal learning