|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 202, Issue 22 3069-3080, Copyright © 1999 by Company of Biologists
JOURNAL ARTICLES |
P Domenici, J Schmitz and M Jamon
CNRS-NBM, 13402 Marseille Cedex, France and Department of Biological Cybernetics, Faculty of Biology, University of Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany. domenici@barolo.icb.cnr.ge.it.
Curve walking in two species of crayfish, Procambarus clarkii and Astacus leptodactylus, was investigated to test whether the mechanism underlying curve walking is the synchronous action of a centrally pre-programmed leg tripod or whether it is the action of one principal leg that produces the main body yaw torque. Curve walking was induced by an optomotor visual stimulus, and the yaw torque produced by the tethered animals was measured in open-loop conditions. Our main results suggest that the yaw torque oscillations in both P. clarkii and A. leptodactylus are related to the movement of outer leg 4 (i.e. leg 4 on the outside of the turn). That is, the peaks in the yaw torque occur, on average, in synchrony with the power stroke of outer leg 4. When comparing the results of this open-loop experiment on P. clarkii with results previously obtained for curve walking in untethered individuals of the same species, we found a much higher variability in leg coordination in the open-loop situation. Similarly, here we did not find the same level of synchrony in the tripod (formed by outer leg 4 and inner legs 2 and 5) observed during untethered free walking. Therefore, we suggest that tethered conditions may diminish the need for stability and thus allow outer leg 4 to produce a body rotation regardless of the leg stepping configuration. The characteristics of leg 4 are in line with its major role in turning. According to previous studies, legs 4 provide the largest force and the largest step amplitude during walking, and their force includes both a pulling and a pushing component which can facilitate the control of turning. Although it is apparent that outer leg 4 is not the only leg that can produce an inward yaw torque, its major role in modulating the yaw torque suggests that there may be a specific, centrally generated control of outer leg 4 during curve walking in crayfish.
This article has been cited by other articles:
|
|
 |
|
  B. Demes, K. J. Carlson, and T. M. Franz Cutting corners: the dynamics of turning behaviors in two primate species J. Exp. Biol., March 1, 2006; 209(5): 927 - 937. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Durr and W. Ebeling The behavioural transition from straight to curve walking: kinetics of leg movement parameters and the initiation of turning J. Exp. Biol., June 15, 2005; 208(12): 2237 - 2252. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Tschuluun, W. M. Hall, and B. Mulloney Limb Movements during Locomotion: Tests of a Model of an Intersegmental Coordinating Circuit J. Neurosci., October 1, 2001; 21(19): 7859 - 7869. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N Copp and M Jamon Kinematics of rotation in place during defense turning in the crayfish Procambarus clarkii J. Exp. Biol., January 2, 2001; 204(3): 471 - 486. [Abstract] [PDF]
|
|
