title: In actio optophysiological analyses reveal functional diversification of dopaminergic neurons in the nematode C. elegans.
abstract: Many neuronal groups such as dopamine-releasing (dopaminergic) neurons are functionally divergent, although the details of such divergence are not well understood. Dopamine in the nematode Caenorhabditis elegans modulates various neural functions and is released from four left-right pairs of neurons. The terminal identities of these dopaminergic neurons are regulated by the same genetic program, and previous studies have suggested that they are functionally redundant. In this study, however, we show functional divergence within the dopaminergic neurons of C. elegans. Because dopaminergic neurons of the animals were supposedly activated by mechanical stimulus upon entry into a lawn of their food bacteria, we developed a novel integrated microscope system that can auto-track a freely-moving (in actio) C. elegans to individually monitor and stimulate the neuronal activities of multiple neurons. We found that only head-dorsal pair of dopaminergic neurons (CEPD), but not head-ventral or posterior pairs, were preferentially activated upon food entry. In addition, the optogenetic activation of CEPD neurons alone exhibited effects similar to those observed upon food entry. Thus, our results demonstrated functional divergence in the genetically similar dopaminergic neurons, which may provide a new entry point toward understanding functional diversity of neurons beyond genetic terminal identification.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanimoto
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Ying Grace
authors.initials: YG
authors.lastname: Zheng
authors.affiliation: Faculty of Science and Technology, Tohoku Bunka Gakuen Univ., Sendai 981-0943, Japan.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Fei
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Fujie
authors.affiliation: Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Koutarou D
authors.initials: KD
authors.lastname: Kimura
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D059290:Dopaminergic Neurons / Q000502:physiology*; D004926:Escherichia coli; D005247:Feeding Behavior / Q000502:physiology; D008124:Locomotion / Q000502:physiology; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D062308:Optogenetics