INTERLIMB DIFFERENCES IN CONTROL OF MULTIJOINT DYNAMICS

Project: Research project

Project Details

Description

DESCRIPTION: (Verbatim from application) Handedness, the manual asymmetry
characterized by the tendency to favor one hand for performance of skilled
unimanual tasks, is a prominent feature of human motor performance that is
believed to result from differences in the neural control of each limb.
However, the precise mechanisms responsible for handedness remain
controversial. The proposed studies build on our current findings, which
indicate interlimb disparities in the control of intersegmental dynamics.
Previous research indicates that reaching movements are initially planned in
terms of task relevant variables, such as hand movement direction and amplitude
(Krakauer and Ghez, 1999), and that this plan must be transformed into muscle
activations in order for movement to take place. This transformation relies on
internal representations of musculoskeletal and task specific dynamics
(Gandolfo, et at, 1996; Goodbody and Wolpert, 1998; Jordan and Rumelhart, 1992;
Lackner and Dizio, 1994; Sainburg, et al, 1999; Shadmehr and Mussa-Ivaldi,
1994). We hypothesize that the dominant arm controller is specialized for
developing and updating such neural representations. To test this hypothesis,
we employ a unique experimental paradigm that we previously developed to
investigate learning of novel intersegmental dynamics with the dominant arm
(Sainburg et al., 1999). We will analyze movement strategies following
adaptation to altered inertial dynamics, imposed by attaching a mass to an
outrigger, either medial or lateral to the forearm. Because this manipulation
specifically alters the amplitude of interaction torques acting between the
segments, we can investigate the extent to which the Central Nervous System
(CNS) represents these dynamics and, in turn, utilizes such representations for
planning and executing subsequent movements. We will compare interlimb
differences in adaptation to novel visual-motor transformations and to novel
inertial dynamics, to determine the level of the motor control process at which
handedness is expressed. We will investigate differences in both anticipatory
mechanisms, as well as, visual and somatosensory based error correction
mechanisms. By specifically manipulating the characteristics of movement
targets, we will determine whether transfer of learning is greater for
movements in which either interaction torques or net torques remain constant.
We will then examine interlimb differences in the extent to which learning
transfers across changes in the relevant torque. These studies will provide a
more thorough understanding of the neural mechanisms underlying handedness,
which is critical for clinical rehabilitation applications that address motor
learning in patients with unilateral movement deficits.
StatusFinished
Effective start/end date4/1/0111/30/11

Funding

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $197,026.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $218,268.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $212,907.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $218,018.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $201,256.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $218,104.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $196,796.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $194,573.00
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development: $218,187.00

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