GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Physiological Society  (2)
Material
Publisher
  • American Physiological Society  (2)
Person/Organisation
Language
Years
Subjects(RVK)
  • 1
    Online Resource
    Online Resource
    The role of intrinsic factors in control of arm movement direction: implications from directional preferences
    American Physiological Society ; 2011
    In:  Journal of Neurophysiology Vol. 105, No. 3 ( 2011-03), p. 999-1010
    Details
    In: Journal of Neurophysiology, American Physiological Society, Vol. 105, No. 3 ( 2011-03), p. 999-1010
    Abstract: The role of extrinsic and intrinsic factors in control of arm movement direction remains under debate. We addressed this question by investigating preferences in selection of movement direction and whether factors causing these preferences have extrinsic or intrinsic nature. An unconstrained free-stroke drawing task was used during which participants produced straight strokes on a horizontal table, choosing the direction and the beginning and end of each stroke arbitrarily. The variation of the initial arm postures across strokes provided a possibility to distinguish between the extrinsic and intrinsic origins of directional biases. Although participants were encouraged to produce strokes equally in all directions, each participant demonstrated preferences for some directions over the others. However, the preferred directions were not consistent across participants, suggesting no directional preferences in extrinsic space. Consistent biases toward certain directions were revealed in intrinsic space representing initial arm postures. Factors contributing to the revealed preferences were analyzed within the optimal control framework. The major bias was explained by a tendency predicted by the leading joint hypothesis (LJH) to minimize active interference with interaction torque generated by shoulder motion at the elbow. Some minor biases may represent movements of minimal inertial resistance or maximal kinematic manipulability. These results support a crucial role of intrinsic factors in control of the movement direction of the arm. Based on the LJH interpretation of the major bias, we hypothesize that the dominant tendency was to minimize neural effort for control of arm intersegmental dynamics. Possible organization of neural processes underlying optimal selection of movement direction is discussed.
    Type of Medium: Online Resource
    ISSN: 0022-3077 , 1522-1598
    URL: Article
    DOI: 10.1152/jn.00630.2010
    RVK:
    XA 10000 ; XA 552555
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2011
    detail.hit.zdb_id: 80161-6
    detail.hit.zdb_id: 1467889-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    A preferred pattern of joint coordination during arm movements with redundant degrees of freedom
    American Physiological Society ; 2014
    In:  Journal of Neurophysiology Vol. 112, No. 5 ( 2014-09-01), p. 1040-1053
    Details
    In: Journal of Neurophysiology, American Physiological Society, Vol. 112, No. 5 ( 2014-09-01), p. 1040-1053
    Abstract: Redundancy of degrees of freedom (DOFs) during natural human movements is a central problem of motor control research. This study tests a novel interpretation that during arm movements, the DOF redundancy is used to support a preferred, simplified joint control pattern that consists of rotating either the shoulder or elbow actively and the other (trailing) joint predominantly passively by interaction and gravitational torques. We previously revealed the preference for this control pattern during nonredundant horizontal arm movements. Here, we studied whether this preference persists during movements with redundant DOFs and the redundancy is used to enlarge the range of directions in which this control pattern can be utilized. A free-stroke drawing task was performed that involved production of series of horizontal center-out strokes in randomly selected directions. Two conditions were used, with the arm's joints unconstrained (U) and constrained (C) to the horizontal plane. In both conditions, directional preferences were revealed and the simplified control pattern was used in the preferred and not in nonpreferred directions. The directional preferences were weaker and the range of preferred directions was wider in the U condition, with higher percentage of strokes performed with the simplified control pattern. This advantage was related to the usage of additional DOFs. We discuss that the simplified pattern may represent a feedforward control strategy that reduces the challenge of joint coordination caused by signal-dependent noise during movement execution. The results suggest a possibility that the simplified pattern is used during the majority of natural, seemingly complex arm movements.
    Type of Medium: Online Resource
    ISSN: 0022-3077 , 1522-1598
    URL: Article
    DOI: 10.1152/jn.00082.2014
    RVK:
    XA 10000 ; XA 552555
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2014
    detail.hit.zdb_id: 80161-6
    detail.hit.zdb_id: 1467889-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...