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Intrinsic electrical properties of spinal motoneurons vary with joint angle. Nat Neurosci 2007 Mar;10(3):363-9

Date

02/13/2007

Pubmed ID

17293858

DOI

10.1038/nn1852

Scopus ID

2-s2.0-33847188064   85 Citations

Abstract

The dendrites of spinal motoneurons amplify synaptic inputs to a marked degree through persistent inward currents (PICs). Dendritic amplification is subject to neuromodulatory control from the brainstem by axons releasing the monoamines serotonin and norepinephrine; however, the monoaminergic projection to the cord is diffusely organized and does not allow independent adjustment of amplification in different motor pools. Using in vivo voltage-clamp techniques, here we show that dendritic PICs in ankle extensor motoneurons in the cat are reduced about 50% by small rotations (+/-10 degrees ) of the ankle joint. This reduction is primarily due to reciprocal inhibition, a tightly focused input shared only among strict muscle antagonists. These results demonstrate how a specific change in limb position can regulate intrinsic cellular properties set by a background of diffuse descending neuromodulation.

Author List

Hyngstrom AS, Johnson MD, Miller JF, Heckman CJ

Author

Allison Hyngstrom PhD Associate Professor in the Physical Therapy department at Marquette University




MESH terms used to index this publication - Major topics in bold

Animals
Ankle Joint
Cats
Decerebrate State
Membrane Potentials
Motor Neurons
Patch-Clamp Techniques
Posture
Regression Analysis
Robotics
Spinal Cord