title: Fractal correlation of initial trajectory dynamics vanishes at the movement end point in human rapid goal-directed movements.
abstract: Many researchers have investigated the variability of discrete goal-directed movements. However, a possible time-dependent property for them has been ignored. We investigated the time-dependent property of the kinematic variability in human rapid goal-directed movements by using fractal analysis. The variability of the peak acceleration had fractal time correlation characterized by a non-negligible frequency-spectral exponent (beta=0.3). This beta value was reduced at the peak velocity (beta=0.2) and nearly reached zero at the peak movement amplitude, indicating that the variability became white noise with no time correlation. A similar result was observed in the progress of the positional trajectory. The functional significance of this phenomenon for the goal-directed task demand is discussed.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku Tokyo 153-8902, Japan. mmkt@gb4.so-net.ne.jp
authors.forename: M
authors.initials: M
authors.lastname: Miyazaki
authors.forename: H
authors.initials: H
authors.lastname: Kadota
authors.forename: K
authors.initials: K
authors.lastname: Kudo
authors.forename: K
authors.initials: K
authors.lastname: Masani
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuki
mesh_terms: D000054:Acceleration; D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D017709:Fractals; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*