Lim, Maria AChitturi, JyothsnaLaskova, ValeriyaMeng, JunFindeis, DanielWiekenberg, AnneMulcahy, BenLuo, LinjiaoLi, YanLu, YangningHung, WesleyQu, YixinHo, Chi-YipHolmyard, DouglasJi, NiMcWhirter, RebeccaSamuel, AraviMiller, David MSchnabel, RalfCalarco, John AZhen, Mei2016-12-022016Lim, M. A., J. Chitturi, V. Laskova, J. Meng, D. Findeis, A. Wiekenberg, B. Mulcahy, et al. 2016. “Neuroendocrine modulation sustains the C. elegans forward motor state.” eLife 5 (1): e19887. doi:10.7554/eLife.19887. http://dx.doi.org/10.7554/eLife.19887.2050-084Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:29626191Neuromodulators shape neural circuit dynamics. Combining electron microscopy, genetics, transcriptome profiling, calcium imaging, and optogenetics, we discovered a peptidergic neuron that modulates C. elegans motor circuit dynamics. The Six/SO-family homeobox transcription factor UNC-39 governs lineage-specific neurogenesis to give rise to a neuron RID. RID bears the anatomic hallmarks of a specialized endocrine neuron: it harbors near-exclusive dense core vesicles that cluster periodically along the axon, and expresses multiple neuropeptides, including the FMRF-amide-related FLP-14. RID activity increases during forward movement. Ablating RID reduces the sustainability of forward movement, a phenotype partially recapitulated by removing FLP-14. Optogenetic depolarization of RID prolongs forward movement, an effect reduced in the absence of FLP-14. Together, these results establish the role of a neuroendocrine cell RID in sustaining a specific behavioral state in C. elegans. DOI: http://dx.doi.org/10.7554/eLife.19887.001en-USpeptidergic neuronsneuroendocrinemotor stateRNA profilingJournal Article2016-12-0210.7554/eLife.19887