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Effect of spinal cord injury on neural encoding of spontaneous postural perturbations in the hindlimb sensorimotor cortex
Journal article   Open access   Peer reviewed

Effect of spinal cord injury on neural encoding of spontaneous postural perturbations in the hindlimb sensorimotor cortex

Jaimie B Dougherty, Gregory D Disse, Nathaniel R Bridges and Karen A Moxon
Journal of neurophysiology, v 126(5), pp 1555-1567
01 Nov 2021
DOI: https://doi.org/10.1152/jn.00727.2020
PMID: 34379540
Featured in Collection :   UN Sustainable Development Goals @ Drexel
url
https://doi.org/10.1152/jn.00727.2020View
Published, Version of Record (VoR)Open Access (License Unspecified),  Open

Abstract

Animals Behavior, Animal - physiology Disease Models, Animal Electrophysiological Phenomena - physiology Hindlimb - physiopathology Neurons - physiology Postural Balance - physiology Posture - physiology Rats Rats, Long-Evans Sensorimotor Cortex - physiopathology Spinal Cord Injuries - physiopathology
Supraspinal signals play a significant role in compensatory responses to postural perturbations. Although the cortex is not necessary for basic postural tasks in intact animals, its role in responding to unexpected postural perturbations after spinal cord injury (SCI) has not been studied. To better understand how SCI impacts cortical encoding of postural perturbations, the activity of single neurons in the hindlimb sensorimotor cortex (HLSMC) was recorded in the rat during unexpected tilts before and after a complete midthoracic spinal transection. In a subset of animals, limb ground reaction forces were also collected. HLSMC activity was strongly modulated in response to different tilt profiles. As the velocity of the tilt increased, more information was conveyed by the HLSMC neurons about the perturbation due to increases in both the number of recruited neurons and the magnitude of their responses. SCI led to attenuated and delayed hindlimb ground reaction forces. However, HLSMC neurons remained responsive to tilts after injury but with increased latencies and decreased tuning to slower tilts. Information conveyed by cortical neurons about the tilts was therefore reduced after SCI, requiring more cells to convey the same amount of information as before the transection. Given that reorganization of the hindlimb sensorimotor cortex in response to therapy after complete midthoracic SCI is necessary for behavioral recovery, this sustained encoding of information after SCI could be a substrate for the reorganization that uses sensory information from above the lesion to control trunk muscles that permit weight-supported stepping and postural control. The role of cortical circuits in the encoding of posture and balance is of interest for developing therapies for spinal cord injury. This work demonstrated that unexpected postural perturbations are encoded in the hindlimb sensorimotor cortex even in the absence of hindlimb sensory feedback. In fact, the hindlimb sensorimotor cortex continues to encode for postural perturbations after complete spinal transection.

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UN Sustainable Development Goals (SDGs)

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#3 Good Health and Well-Being

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Collaboration types
Domestic collaboration
Web of Science research areas
Neurosciences
Physiology
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