Imperial College London
Alternate

ProfessorEtienneBurdet

Faculty of Engineering, Department of Bioengineering

Professor of Human Robotics
 
 
 
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Contact

 

e.burdet Website

 
 
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Location

 

419BSir Michael Uren HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Borzelli:2018:10.1371/journal.pone.0205911,
author = {Borzelli, D and Cesqui, B and Berger, DJ and Burdet, E and d'Avella, A},
doi = {10.1371/journal.pone.0205911},
journal = {PLoS ONE},
title = {Muscle patterns underlying voluntary modulation of co-contraction},
url = {http://dx.doi.org/10.1371/journal.pone.0205911},
volume = {13},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Manipulative actions involving unstable interactions with the environment require controlling mechanical impedance through muscle co-contraction. While much research has focused on how the central nervous system (CNS) selects the muscle patterns underlying a desired movement or end-point force, the coordination strategies used to achieve a desired end-point impedance have received considerably less attention. We recorded isometric forces at the hand and electromyographic (EMG) signals in subjects performing a reaching task with an external disturbance. In a virtual environment, subjects displaced a cursor by applying isometric forces and were instructed to reach targets in 20 spatial locations. The motion of the cursor was then perturbed by disturbances whose effects could be attenuated by increasing co-contraction. All subjects could voluntarily modulate co-contraction when disturbances of different magnitudes were applied. For most muscles, activation was modulated by target direction according to a cosine tuning function with an offset and an amplitude increasing with disturbance magnitude. Co-contraction was characterized by projecting the muscle activation vector onto the null space of the EMG-to-force mapping. Even in the baseline the magnitude of the null space projection was larger than the minimum magnitude required for non-negative muscle activations. Moreover, the increase in co-contraction was not obtained by scaling the baseline null space projection, scaling the difference between the null space projections in any block and the projection of the non-negative minimum-norm muscle vector, or scaling the difference between the null space projections in the perturbed blocks and the baseline null space projection. However, the null space projections in the perturbed blocks were obtained by linear combination of the baseline null space projection and the muscle activation used to increase co-contraction without generating any force. The failure of scaling rul
AU  - Borzelli,D
AU  - Cesqui,B
AU  - Berger,DJ
AU  - Burdet,E
AU  - d'Avella,A
DO  - 10.1371/journal.pone.0205911
PY  - 2018///
SN  - 1932-6203
TI  - Muscle patterns underlying voluntary modulation of co-contraction
T2  - PLoS ONE
UR  - http://dx.doi.org/10.1371/journal.pone.0205911
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000447761400025&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/65219
VL  - 13
ER  -
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