MDN brain descending neurons coordinately activate backward and inhibit forward locomotion
- Howard Hughes Medical Institute, University of Oregon, United States
- Howard Hughes Medical Institute, University of Oregonof Oregon, United States
- Howard Hughes Medical Institute, United States
Abstract
Command-like descending neurons can induce many behaviors, such as backward locomotion, escape, feeding, courtship, egg-laying, or grooming (we define 'command-like neuron' as a neuron whose activation elicits or 'commands' a specific behavior). In most animals it remains unknown how neural circuits switch between antagonistic behaviors: via top-down activation/inhibition of antagonistic circuits or via reciprocal inhibition between antagonistic circuits. Here we use genetic screens, intersectional genetics, circuit reconstruction by electron microscopy, and functional optogenetics to identify a bilateral pair of Drosophila larval 'mooncrawler descending neurons' (MDNs) with command-like ability to coordinately induce backward locomotion and block forward locomotion; the former by stimulating a backward-active premotor neuron, and the latter by disynaptic inhibition of a forward-specific premotor neuron. In contrast, direct monosynaptic reciprocal inhibition between forward and backward circuits was not observed. Thus, MDNs coordinate a transition between antagonistic larval locomotor behaviors. Interestingly, larval MDNs persist into adulthood, where they can trigger backward walking. Thus, MDNs induce backward locomotion in both limbless and limbed animals.
Data availability
All data presented in this study are available as supplemental files.
Article and author information
Author details
Funding
National Institutes of Health (HD27056)
- Richard D Fetter
Howard Hughes Medical Institute (HHMI)
- Aref Arzan Zarin
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2018, Carreira-Rosario et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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MDN brain descending neurons coordinately activate backward and inhibit forward locomotion
eLife 7:e38554.
https://doi.org/10.7554/eLife.38554
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