Related Experiment Video
Updated: Jul 13, 2026

Corticospinal Excitability Modulation During Action Observation
Published on: December 31, 2013
Does abnormal spinal reciprocal inhibition lead to co-contraction of antagonist motor units? A modeling study
1Department of Computing Science and Mathematics, University of Stirling, Stirling FK9 4LA, Scotland. vcu@cs.stir.ac.uk
Abstract:
It is suggested that co-contraction of antagonist motor units perhaps due to abnormal disynaptic I(a) reciprocal inhibition is responsible for Parkinsonian rigidity. A neural model of Parkinson's disease bradykinesia is extended to incorporate the effects of spindle feedback on key cortical cells and examine the effects of dopamine depletion on spinal activities. Simulation results show that although reciprocal inhibition is reduced in DA depleted case, it doesn't lead to co-contraction of antagonist motor neurons. Implications to Parkinsonian rigidity are discussed.
Related Concept Videos
Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
Somatic Spinal Reflexes
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...

