Title
Neuromotor Noise, Error Tolerance And Velocity-Dependent Costs In Skilled Performance
Abstract
In motor tasks with redundancy neuromotor noise can lead to variations in execution while achieving relative invariance in the result. The present study examined whether humans find solutions that are tolerant to intrinsic noise. Using a throwing task in a virtual set-up where an infinite set of angle and velocity combinations at ball release yield throwing accuracy, our computational approach permitted quantitative predictions about solution strategies that are tolerant to noise. Based on a mathematical model of the task expected results were computed and provided predictions about error-tolerant strategies (Hypothesis 1). As strategies can take on a large range of velocities, a second hypothesis was that subjects select strategies that minimize velocity at release to avoid costs associated with signal-or velocity-dependent noise or higher energy demands (Hypothesis 2). Two experiments with different target constellations tested these two hypotheses. Results of Experiment 1 showed that subjects chose solutions with high error-tolerance, although these solutions also had relatively low velocity. These two benefits seemed to outweigh that for many subjects these solutions were close to a high-penalty area, i.e. they were risky. Experiment 2 dissociated the two hypotheses. Results showed that individuals were consistent with Hypothesis 1 although their solutions were distributed over a range of velocities. Additional analyses revealed that a velocity-dependent increase in variability was absent, probably due to the presence of a solution manifold that channeled variability in a task-specific manner. Hence, the general acceptance of signal-dependent noise may need some qualification. These findings have significance for the fundamental understanding of how the central nervous system deals with its inherent neuromotor noise.
Year
DOI
Venue
2011
10.1371/journal.pcbi.1002159
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
mathematical model,motor skills,statistical distributions,linear regression analysis,sensory systems,noise reduction,central nervous system,ellipses,linear models,covariance,arm,human performance
Noise reduction,Biology,Linear model,Control theory,Throwing,Motor control,Infinite set,Probability distribution,Redundancy (engineering),Bioinformatics,Statistics,Covariance
Journal
Volume
Issue
ISSN
7
9
1553-7358
Citations 
PageRank 
References 
5
0.65
4
Authors
4
Name
Order
Citations
PageRank
Dagmar Sternad19121.36
Masaki O Abe271.36
Xiaogang Hu351.32
Hermann Müller450.65