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Updated: Jun 26, 2026
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Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI
Published on: April 18, 2011
[Neural mechanisms underlying spasticity]
Masanori Nagaoka1, Naoyuki Kakuda
1Department of Rehabilitation Medicine, Juntendo University Graduate School, Bunkyo-Ku, Tokyo 113-8421, Japan.
Brain and Nerve = Shinkei Kenkyu No Shinpo
|December 30, 2008
Summary
Spasticity, a disorder affecting muscle tone, presents with varied symptoms. This study explores potential spinal mechanisms, including altered stretch reflexes and neuronal pathways, contributing to spasticity.
Area of Science:
- Neuroscience
- Physiology
Context:
- Spasticity is a complex neurological disorder characterized by increased muscle tone and exaggerated reflexes.
- The cardinal feature of spasticity is often described as an increase in velocity-dependent stretch reflexes.
Purpose:
- To explore the underlying mechanisms of increased stretch reflexes in spasticity.
- To discuss potential spinal mechanisms, including changes in gamma innervations and spinal motoneurons.
Summary:
- Spasticity exhibits variable signs and symptoms, with increased velocity-dependent stretch reflexes being a key characteristic.
- Two proposed mechanisms for exaggerated reflexes involve alterations in gamma innervations and spinal motoneurons.
- While gamma innervations show differences during voluntary contraction in spasticity, resting muscle changes are less clear. Other candidate spinal mechanisms include alterations in presynaptic inhibition, reciprocal Ia inhibition, recurrent inhibition, and autogenic Ib inhibition.
Impact:
- This research contributes to a deeper understanding of the neurophysiological basis of spasticity.
- Identifying specific spinal mechanisms can inform the development of targeted therapeutic interventions for spasticity management.
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