The Journal of Neuroscience, June 1, 1999, 19(11):4634-4643
Sensory Feedback Can Coordinate the Swimming Activity of the
Leech
Xintian
Yu,
Binh
Nguyen, and
W. Otto
Friesen
Department of Biology, National Science Foundation Center for
Biological Timing, University of Virginia, Charlottesville, Virginia
22903-2477
Previous studies showed that sensory feedback from the body wall is
important and sometimes critical for generating normal, robust swimming
activity in leeches. In this paper, we evaluate the role of sensory
feedback in intersegmental coordination using both behavioral and
physiological measurements. We severed the ventral nerve cord of
leeches in midbody and then made video and in situ
extracellular recordings from swimming animals. Our
electrophysiological recordings unequivocally demonstrate that active
intersegmental coordination occurs in leeches with severed nerve cords,
refuting Schülter's (1933) earlier conclusions that
sensory feedback cannot coordinate swimming activity. Intersegmental
coordination can in fact be achieved by sensory feedback alone, without
the intersegmental interactions conveyed by the nerve cord.
Key words:
leech; swimming; sensory feedback; intersegmental
coordination; CPG; oscillator; locomotion
Copyright © 1999 Society for Neuroscience 0270-6474/99/19114634-10$05.00/0