QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online November 19, 2004
Journal of Experimental Biology 207, 4427-4438 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01282

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dunbar, D. C. Search for Related Content PubMed PubMed Citation Articles by Dunbar, D. C.

Stabilization and mobility of the head and trunk in vervet monkeys (Cercopithecus aethiops) during treadmill walks and gallops

Donald C. Dunbar

Department of Anatomy and Caribbean Primate Research Center, School of Medicine, University of Puerto Rico, PO Box 365067, San Juan, PR 00936-5067, USA

e-mail: ddunbar{at}rcm.upr.edu

Accepted 15 September 2004

The brain requires internal or external reference frames to determine body orientation in space. These frames may change, however, to meet changing conditions. During quadrupedal overground locomotion by monkeys, the head rotates on a stabilized trunk during walking, but the trunk rotates on a stabilized head during galloping. Do the same movement patterns occur during in-place locomotion? Head and trunk pitch rotations were measured, and yaw and roll rotations estimated from cine films of three adult vervet monkeys (Cercopithecus aethiops L. 1758) walking and galloping quadrupedally on a treadmill. Head and trunk rotational patterns during treadmill walks were comparable to the patterns found during overground walks. The rotational velocities of these segments during both treadmill walks and gallops were also comparable to the velocities found during natural locomotion. By contrast, whereas head and trunk rotational patterns during treadmill gallops did occur that were comparable to the patterns practiced during overground gallops, a significantly different pattern involving large and simultaneous head and trunk rotations was more commonly observed. Simultaneous head and trunk rotations may be possible during treadmill gallops because the fixed visual surround is providing an adequate spatial reference frame. Alternatively, or in addition to this visual information, a re-weighting in other sensory modalities may be occurring. Specifically, the vestibular inputs used during overground locomotion to reference gravity or a gravity-derived vector may become less important than proprioceptive inputs that are using the treadmill belt surface as a reference. Regardless, the spatial reference frame being used, blinks that occur at specific times during the largest head yaw rotations may be necessary to avoid the initiation of unwanted and potentially destabilizing lateral sway brought on by sudden increases in optic flow velocity.

Key words: spatial reference frames, pitch, yaw, roll, gaze, visual input, optic flow, blinks, vestibular input, proprioception, sensory reweighting, quadrupedal locomotion

This article has been cited by other articles:

				L. D. Maes, M. Herbin, R. Hackert, V. L. Bels, and A. Abourachid Steady locomotion in dogs: temporal and associated spatial coordination patterns and the effect of speed J. Exp. Biol., January 1, 2008; 211(1): 138 - 149. [Abstract] [Full Text] [PDF]