Somatosensory control of balance during locomotion in decerebrated cat

Abstract

Postmammillary decerebrated cats can generate stepping on a moving treadmill belt when the brain stem or spinal cord is stimulated tonically and the hindquarters are supported both vertically and laterally. While adequate propulsion seems to be generated by the hindlimbs under these conditions, the ability to sustain equilibrium during locomotion has not been examined extensively. We found that tonic epidural spinal cord stimulation (5 Hz at L5) of decerebrated cats initiated and sustained unrestrained weight-bearing hindlimb stepping for extended periods. Detailed analyses of the relationships among hindlimb muscle EMG activity and trunk and limb kinematics and kinetics indicated that the motor circuitries in decerebrated cats actively maintain equilibrium during walking, similar to that observed in intact animals. Because of the suppression of vestibular, visual, and head-neck-trunk sensory input, balance-related adjustments relied entirely on the integration of somatosensory information arising from the moving hindquarters. In addition to dynamic balance control during unperturbed locomotion, sustained stepping could be reestablished rapidly after a collapse or stumble when the hindquarters switched from a restrained to an unrestrained condition. Deflecting the body by pulling the tail laterally induced adaptive modulations in the EMG activity, step cycle features, and left-right ground reaction forces that were sufficient to maintain lateral stability. Thus the brain stem-spinal cord circuitry of decerebrated cats in response to tonic spinal cord stimulation can control dynamic balance during locomotion using only somatosensory input.

Functional Neurorehabilitation - The Locomotor Quadrupedal Animal Training Adapted to the Bipedal Human

“…The neural mechanism associated with posture and locomotion is a rehabilitation method that is essentially to the LT, as well as the electromyostimulation, which allows a direct stimulation of afferent fibers at the level of the dorsal horn of the spinal cord (Musienko, Courtine, et al, 2012).…”

“…The postural system depends on a world of integrations involving vision, the vestibular and somatosensory inputs (Musienko, Courtine, et al, 2012). The orientation of the head is established with the vestibular and visual information while the somatosensory information allows the stabilization of the body during the postural standing (Musienko, Courtine, et al, 2012).…”

“…The orientation of the head is established with the vestibular and visual information while the somatosensory information allows the stabilization of the body during the postural standing (Musienko, Courtine, et al, 2012).…”

The importance of the quadruped animal model in functional neurorehabilitation in the human biped

“…We can summarize by saying that the stimulation may be, as stated above, by electric epidural stimulation, but also by transcutaneous stimulation, direct electromagnetic stimulation of the spinal cord and rhythmic movements in standing posture, depending on the supraspinal influence and on the rhythmic capacity of the spinal circuits (Musienko et al, 2012;Solopova et al, 2015).…”

“…The MLR can also be stimulated by dorsolateral funiculus (DLF) fibers, originated between C1 and L1 spinal cord segments. These fibres (DLF and LPR) can induce a quadruped locomotor gait through the brainstem (Lavron et al, 2014;Harkema et al, 2012;Musienko et al, 2012).…”