title: The duration of reaching movement is longer than predicted by minimum variance.
abstract: Whether the central nervous system minimizes variability or effort in planning arm movements can be tested by measuring the preferred movement duration and end-point variability. Here we conducted an experiment in which subjects performed arm reaching movements without visual feedback in fast-, medium-, slow-, and preferred-duration conditions. Results show that 1) total end-point variance was smallest in the medium-duration condition and 2) subjects preferred to carry out movements that were slower than this medium-duration condition. A parsimonious explanation for the overall pattern of end-point errors across fast, medium, preferred, and slow movement durations is that movements are planned to minimize effort as well as end-point error due to both signal-dependent and constant noise.
authors: Neuroscience Graduate Program, University of Southern California, Los Angeles, California.
authors: Chunji
authors: C
authors: Wang
authors: Neuroscience Graduate Program, University of Southern California, Los Angeles, California.
authors: Yupeng
authors: Y
authors: Xiao
authors: Bioengineering Department, Imperial College, London, United Kingdom; and.
authors: Etienne
authors: E
authors: Burdet
authors: Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California.
authors: James
authors: J
authors: Gordon
authors: Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California schweigh@usc.edu.
authors: Nicolas
authors: N
authors: Schweighofer
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: constant and signal-dependent noise; effort minimization; minimum variance model; reaching movements