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Human motor adaptation in whole body motion

View Article: PubMed Central - PubMed

ABSTRACT

The main role of the sensorimotor system of an organism is to increase the survival of the species. Therefore, to understand the adaptation and optimality mechanisms of motor control, it is necessary to study the sensorimotor system in terms of ecological fitness. We designed an experimental paradigm that exposed sensorimotor system to risk of injury. We studied human subjects performing uncon- strained squat-to-stand movements that were systematically subjected to non-trivial perturbation. We found that subjects adapted by actively compensating the perturbations, converging to movements that were different from their normal unperturbed squat-to-stand movements. Furthermore, the adapted movements had clear intrinsic inter-subject differences which could be explained by different adapta- tion strategies employed by the subjects. These results suggest that classical optimality measures of physical energy and task satisfaction should be seen as part of a hierarchical organization of optimality with safety being at the highest level. Therefore, in addition to physical energy and task fulfillment, the risk of injury and other possible costs such as neural computational overhead have to be considered when analyzing human movement.

No MeSH data available.


Related in: MedlinePlus

Catch trial simulations with a single-set of feedback controller parameters.Green broken line represent simulated catch trials for individual subjects. Apart from one obvious outlier (subject 5), a single set of feedback control parameters is sufficient to reproduce the trajectories of all the subjects to a high precision.
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f8: Catch trial simulations with a single-set of feedback controller parameters.Green broken line represent simulated catch trials for individual subjects. Apart from one obvious outlier (subject 5), a single set of feedback control parameters is sufficient to reproduce the trajectories of all the subjects to a high precision.

Mentions: Using the least square method, we determined a single set of the feedback controller parameters (P and D gains) that best fit the simulated catch trial trajectories with the experimentally obtained catch trials trajectories of all subjects (Fig. 8). We found out that a single set of feedback control parameters is sufficient to reproduce the catch trial trajectories of all the subjects to a high precision, except one outlier (subject 5). Allowing individual setting of the feedback control parameters even further improves the individual fit of the simulated catch trajectories with the experimentally determined catch trials trajectories of the individual subjects (Fig. 9).


Human motor adaptation in whole body motion
Catch trial simulations with a single-set of feedback controller parameters.Green broken line represent simulated catch trials for individual subjects. Apart from one obvious outlier (subject 5), a single set of feedback control parameters is sufficient to reproduce the trajectories of all the subjects to a high precision.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016968&req=5

f8: Catch trial simulations with a single-set of feedback controller parameters.Green broken line represent simulated catch trials for individual subjects. Apart from one obvious outlier (subject 5), a single set of feedback control parameters is sufficient to reproduce the trajectories of all the subjects to a high precision.
Mentions: Using the least square method, we determined a single set of the feedback controller parameters (P and D gains) that best fit the simulated catch trial trajectories with the experimentally obtained catch trials trajectories of all subjects (Fig. 8). We found out that a single set of feedback control parameters is sufficient to reproduce the catch trial trajectories of all the subjects to a high precision, except one outlier (subject 5). Allowing individual setting of the feedback control parameters even further improves the individual fit of the simulated catch trajectories with the experimentally determined catch trials trajectories of the individual subjects (Fig. 9).

View Article: PubMed Central - PubMed

ABSTRACT

The main role of the sensorimotor system of an organism is to increase the survival of the species. Therefore, to understand the adaptation and optimality mechanisms of motor control, it is necessary to study the sensorimotor system in terms of ecological fitness. We designed an experimental paradigm that exposed sensorimotor system to risk of injury. We studied human subjects performing uncon- strained squat-to-stand movements that were systematically subjected to non-trivial perturbation. We found that subjects adapted by actively compensating the perturbations, converging to movements that were different from their normal unperturbed squat-to-stand movements. Furthermore, the adapted movements had clear intrinsic inter-subject differences which could be explained by different adapta- tion strategies employed by the subjects. These results suggest that classical optimality measures of physical energy and task satisfaction should be seen as part of a hierarchical organization of optimality with safety being at the highest level. Therefore, in addition to physical energy and task fulfillment, the risk of injury and other possible costs such as neural computational overhead have to be considered when analyzing human movement.

No MeSH data available.


Related in: MedlinePlus