title: Circadian rhythms in neuronal activity propagate through output circuits.
abstract: Twenty-four hour rhythms in behavior are organized by a network of circadian pacemaker neurons. Rhythmic activity in this network is generated by intrinsic rhythms in clock neuron physiology and communication between clock neurons. However, it is poorly understood how the activity of a small number of pacemaker neurons is translated into rhythmic behavior of the whole animal. To understand this, we screened for signals that could identify circadian output circuits in Drosophila melanogaster. We found that leucokinin neuropeptide (LK) and its receptor (LK-R) were required for normal behavioral rhythms. This LK/LK-R circuit connects pacemaker neurons to brain areas that regulate locomotor activity and sleep. Our experiments revealed that pacemaker neurons impose rhythmic activity and excitability on LK- and LK-R-expressing neurons. We also found pacemaker neuron-dependent activity rhythms in a second circadian output pathway controlled by DH44 neuropeptide-expressing neurons. We conclude that rhythmic clock neuron activity propagates to multiple downstream circuits to orchestrate behavioral rhythms.
authors.affiliation: Department of Biology, New York University, New York, New York, USA.|Center for Genomics &Systems Biology, New York University Abu Dhabi Institute, Abu Dhabi, United Arab Emirates.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Cavey
authors.affiliation: Department of Biology, New York University, New York, New York, USA.
authors.forename: Ben
authors.initials: B
authors.lastname: Collins
authors.affiliation: Department of Biology, New York University, New York, New York, USA.
authors.forename: Claire
authors.initials: C
authors.lastname: Bertet
authors.affiliation: Department of Biology, New York University, New York, New York, USA.|Center for Genomics &Systems Biology, New York University Abu Dhabi Institute, Abu Dhabi, United Arab Emirates.|Program in Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
authors.forename: Justin
authors.initials: J
authors.lastname: Blau
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D029721:Drosophila Proteins / Q000032:analysis / Q000096:biosynthesis; D004331:Drosophila melanogaster; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009415:Nerve Net / Q000737:chemistry / Q000502:physiology*; D009474:Neurons / Q000737:chemistry / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins