Journal of Comparative Physiology A

, Volume 200, Issue 7, pp 641–656

Sensory-evoked turning locomotion in red-eared turtles: kinematic analysis and electromyography

Authors

  • Dan B. Welch
    • Department of Growth Development and StructureSouthern Illinois University, School of Dental Medicine
    • Department of Cell Biology and NeuroscienceUniversity of California
Original Paper

DOI: 10.1007/s00359-014-0908-0

Cite this article as:
Welch, D.B. & Currie, S.N. J Comp Physiol A (2014) 200: 641. doi:10.1007/s00359-014-0908-0

Abstract

We examined the limb kinematics and motor patterns that underlie sensory-evoked turning locomotion in red-eared turtles. Intact animals were held by a band-clamp in a water-filled tank. Turn-swimming was evoked by slowly rotating turtles to the right or left via a motor connected to the shaft of the band-clamp. Animals executed sustained forward turn-swimming against the direction of the imposed rotation. We recorded video of turn-swimming and computer-analyzed the limb and head movements. In a subset of turtles, we also recorded electromyograms from identified limb muscles. Turning exhibited a stereotyped pattern of (1) coordinated forward swimming in the hindlimb and forelimb on the outer side of the turn, (2) back-paddling in the hindlimb on the inner side, (3) a nearly stationary, “braking” forelimb on the inner side, and (4) neck bending toward the direction of the turn. Reversing the rotation caused animals to switch the direction of their turns and the asymmetric pattern of right and left limb activities. Preliminary evidence suggested that vestibular inputs were sufficient to drive the behavior. Sensory-evoked turning may provide a useful experimental platform to examine the brainstem commands and spinal neural networks that underlie the activation and switching of different locomotor forms.

Keywords

Turtle Locomotion Turning Kinematics Motor patterns

Abbreviations

BP

Back-paddle

EE

Elbow extensor

EMG

Electromyogram

FS

Forward swim

HP

Hip protractor

HR

Hip retractor

KE

Knee extensor

SP

Shoulder protractor

SR

Shoulder retractor

Copyright information

© Springer-Verlag Berlin Heidelberg 2014