Experimental Brain Research

, Volume 131, Issue 1, pp 22–32 | Cite as

Coordination of the eyes and head: movement kinematics

  • Edward G. Freedman
  • David L. Sparks
Research Article


When the head is restrained, saccades are characterized by lawful relationships between movement amplitude, peak velocity, and duration. In addition, the spatiotemporal progression of saccades (i.e., movement kinematics) is predictable if saccade amplitude and direction are known. However, when the head is free to move, changes in the direction of the line of sight (gaze shifts) often involve saccades associated with simultaneous head movements. The metrics (duration, amplitude, peak velocity) and kinematics of saccades occurring in conjunction with head movements cannot be predicted on the basis of saccade amplitude and direction alone. For example, when the head is unrestrained, velocity profiles of 35° eye movements can be symmetrical and might have peaks ~600°/s. But, 35° eye movements can also have peak velocities of ~300°/s and have velocity profiles with two pronounced peaks: an initial peak followed by a reduction and subsequent increase in velocity. Saccade amplitude and direction are insufficient to predict the shape of the velocity profile. However, as illustrated in this report, if the amplitude of the concurrent head movement is taken into account, saccade kinematics are predictable even during gaze shifts with large head components. The data presented here are indicative of an interaction between eye and head motor systems in which head movement commands alter the execution of concurrent saccades.

Gaze shifts Kinematics Eye-head interactions 


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Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • Edward G. Freedman
    • 1
  • David L. Sparks
    • 2
  1. 1.Department of Neurobiology and Anatomy and Center for Visual Science, Box 603, University of Rochester, 601 Elmwood Ave., Rochester, NY 14642, USA
  2. 2.Division of Neuroscience, Baylor College of Medicine, Houston, TX, USA

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