Logo image
Back
Effects of dorsal root cut on the forces evoked by spinal microstimulation in the spinalized frog
Journal article   Peer reviewed

Effects of dorsal root cut on the forces evoked by spinal microstimulation in the spinalized frog

E P Loeb, S F Giszter, P Borghesani and E Bizzi
Somatosensory & motor research, v 10(1)
1993
DOI: https://doi.org/10.3109/08990229309028826
PMID: 8484299

Abstract

Motor Activity - physiology Animals Electric Stimulation Sensory Thresholds - physiology Muscle Contraction - physiology Spinal Cord - physiology Ganglia, Spinal - physiology Hindlimb - innervation Electromyography Rana catesbeiana Joints - innervation
Spinalized frogs were microstimulated in the intermediate grey layers of the lumbar spinal cord; the forces evoked in the hindlimb were measured at several limb positions. The data were expressed as force fields. After the collection of many force fields, the dorsal roots were cut with the stimulating electrode in place, and the position-dependent stimulation-evoked forces were again measured repeatedly. We found that the position-dependent pattern of evoked forces--the force fields--did not change after the dorsal roots were cut. In other words, the postcut evoked forces pointed in the same direction as the precut evoked forces. This result was predicted and confirmed by the muscle activations (EMGs): Before and after the dorsal roots were cut, the same muscles were activated in the same proportions. In all limb positions, the rank ordering of the muscle activations remained fixed. The stimulation needed to evoke forces was increased by deafferentation, and there were subtle changes in the force magnitudes that were consistent with a linearization of the muscle stiffness by the afferents. We conclude that the microstimulation activated specific muscle synergies that resulted in limb forces pointing toward a particular posture. The patterns of evoked forces were predominantly attributable to feedforward activation of these muscle synergies.

Metrics

13 Record Views
24 citations in Web of Science
27 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Web of Science research areas
Neurosciences
Logo image