Corticomotor Excitability of Arm Muscles Modulates According to Static Position and Orientation of the Upper Limb

AbstractOBJECTIVE: We investigated how multi-joint changes in upper limb posture impact the corticomotor excitability of the posterior deltoid (PD) and biceps brachii (BIC), and evaluated whether postural variations in excitability related directly to changes in target muscle length. METHODS: The amplitude of individual motor evoked potentials (MEPs) was evaluated in each of thirteen different static postures. Four functional postures were investigated that varied in shoulder and elbow angle, while the forearm was positioned in each of three orientations. Posture-related changes in muscle lengths were assessed using a biomechanical arm model. Additionally, M-waves were evoked in the BIC in each of three forearm orientations to assess the impact of posture on recorded signal characteristics. RESULTS: BIC-MEP amplitudes were altered by shoulder and elbow posture, and demonstrated robust changes according to forearm orientation. Observed changes in BIC-MEP amplitudes exceeded those of the M-waves. PD-MEP amplitudes changed predominantly with shoulder posture, but were not completely independent of influence from forearm orientation. CONCLUSIONS: Results provide evidence that overall corticomotor excitability can be modulated according to multi-joint upper limb posture. SIGNIFICANCE: The ability to alter motor pathway excitability using static limb posture suggests the importance of posture selection during rehabilitation aimed at retraining individual muscle recruitment and/or overall coordination patterns.

Download publication

Related Resources

See what’s new.



The Role of Visualization in the Naturalization of Remote Software Immigrants

Software development is commonly becoming a globally distributed task,…



Fast Fluid Dynamics on the Single-chip Cloud Computer

Fast simulation of incompressible fluid flows is necessary for…



Upper Extremity Anatomy, Kinesiology, and Function



Generalized doubling constructions for constant mean curvature hypersurfaces in the (n+1)-sphere

The (n+1)-sphere contains a simple family of constant mean curvature…

Get in touch

Something pique your interest? Get in touch if you’d like to learn more about Autodesk Research, our projects, people, and potential collaboration opportunities.

Contact us