Motor neurons tune premotor activity in a vertebrate central pattern generator

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Publication Type journal article
School or College College of Science
Department Biology
Creator Lawton, Kristy J.
Other Author Perry, Wick M.; Zornik, Erik
Title Motor neurons tune premotor activity in a vertebrate central pattern generator
Date 2017
Description Central patterns generators (CPGs) are neural circuits that drive rhythmic motor output without sensory feedback. Vertebrate CPGs are generally believed to operate in a top-down manner in which premotor interneurons activate motor neurons that in turn drive muscles. In contrast, the frog (Xenopus laevis) vocal CPG contains a functionally unexplored neuronal projection from the motor nucleus to the premotor nucleus, indicating a recurrent pathway that may contribute to rhythm generation. In this study, we characterized the function of this bottom-up connection. The X. laevis vocal CPG produces a 50-60 Hz "fast trill" song used by males during courtship. We recorded "fictive vocalizations" in the in vitro CPG from the laryngeal nerve while simultaneously recording premotor activity at the population and single-cell level. We show that transecting the motor-to-premotor projection eliminated the characteristic firing rate of premotor neurons. Silencing motor neurons with the intracellular sodium channel blocker QX-314 also disrupted premotor rhythms, as did blockade of nicotinic synapses in the motor nucleus (the putative location of motor neuron-to-interneuron connections). Electrically stimulating the laryngeal nerve elicited primarily IPSPs in premotor neurons that could be blocked by a nicotinic receptor antagonist. Our results indicate that an inhibitory signal, activated by motor neurons, is required for proper CPG function. To our knowledge, these findings represent the first example of a CPG in which precise premotor rhythms are tuned by motor neuron activity.
Type Text
Publisher University of Utah
Journal Title Journal of Neuroscience
Volume 37
Issue 12
First Page 3264
Last Page 3275
DOI https://doi.org/10.1523/JNEUROSCI.2755-16.2017
Subject CPG; feed back; synchrony; vocal; vocalization; Xenopus
Language eng
Bibliographic Citation Kristy J. Lawton, Wick M. Perry, Ayako Yamaguchi and Erik Zornik Journal of Neuroscience 22 March 2017, 37 (12) 3264-3275; DOI: https://doi.org/10.1523/JNEUROSCI.2755-16.2017
Relation is Version of http://www.jneurosci.org/content/37/12/3264
Rights Management (c) Ayako Yamaguchi
Format Medium application/pdf
ARK ark:/87278/s6rr6ckc
Setname ir_uspace
ID 1422371
Reference URL https://collections.lib.utah.edu/ark:/87278/s6rr6ckc
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