Experimental Brain Research

, Volume 115, Issue 2, pp 257–266

Kinematics of the freely moving head and neck in the alert cat

  • E. A. Keshner
  • K. D. Statler
  • S. L. Delp
RESEARCH ARTICLE

DOI: 10.1007/PL00005695

Cite this article as:
Keshner, E., Statler, K. & Delp, S. Exp Brain Res (1997) 115: 257. doi:10.1007/PL00005695
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Abstract

 In this study we examined connections between the moment-generating capacity of the neck muscles and their patterns of activation during voluntary head-tracking movements. Three cats lying prone were trained to produce sinusoidal (0.25 Hz) tracking movements of the head in the sagittal plane, and 22.5º and 45º away from the sagittal plane. Radio-opaque markers were placed in the cervical vertebrae, and intramuscular patch electrodes were implanted in five neck muscles, including biventer cervicis, complexus, splenius capitis, occipitoscapularis, and rectus capitis posterior major. Videofluoroscopic images of cervical vertebral motion and muscle electromyographic responses were simultaneously recorded. A three-dimensional biomechanical model was developed to estimate how muscle moment arms and force-generating capacities change during the head-tracking movement. Experimental results demonstrated that the head and vertebrae moved synchronously, but neither the muscle activation patterns nor vertebral movements were constant across trials. Analysis of the biomechanical model revealed that, in some cases, modification of muscle activation patterns was consistent with changes in muscle moment arms or force-generating potential. In other cases, however, changes in muscle activation patterns were observed without changes in muscle moment arms or force-generating potential. This suggests that the moment-generating potential of muscles is just one of the variables that influences which muscles the central nervous system will select to participate in a movement.

Key words Neck muscles Videofluoroscopy Head tracking Moment arms Biomechanical model Cat 

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • E. A. Keshner
    • 1
  • K. D. Statler
    • 1
  • S. L. Delp
    • 1
  1. 1.Sensory Motor Performance Program, Room 1406, Rehabilitation Institute of Chicago, 345 East Superior Street, Chicago, IL 60611, USA; e-mail: eak@nwu.eduUS

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