title: Circadian pacemaker neurons transmit and modulate visual information to control a rapid behavioral response.
abstract: Circadian pacemaker neurons contain a molecular clock that oscillates with a period of approximately 24 hr, controlling circadian rhythms of behavior. Pacemaker neurons respond to visual system inputs for clock resetting, but, unlike other neurons, have not been reported to transmit rapid signals to their targets. Here we show that pacemaker neurons are required to mediate a rapid behavior. The Drosophila larval visual system, Bolwig's organ (BO), projects to larval pacemaker neurons to entrain their clock. BO also mediates larval photophobic behavior. We found that ablation or electrical silencing of larval pacemaker neurons abolished light avoidance. Thus, circadian pacemaker neurons receive input from BO not only to reset the clock but also to transmit rapid photophobic signals. Furthermore, as clock gene mutations also affect photophobicity, the pacemaker neurons modulate the sensitivity of larvae to light, generating a circadian rhythm in visual sensitivity.
authors.affiliation: Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA.
authors.forename: Esteban O
authors.initials: EO
authors.lastname: Mazzoni
authors.forename: Claude
authors.initials: C
authors.lastname: Desplan
authors.forename: Justin
authors.initials: J
authors.lastname: Blau
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001683:Biological Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics*; D003714:Denervation; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000166:cytology / Q000502:physiology*; D007814:Larva / Q000166:cytology / Q000254:growth & development; D055537:Light Signal Transduction / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics; D056950:Period Circadian Proteins; D009435:Synaptic Transmission / Q000235:genetics; D014795:Visual Pathways / Q000166:cytology / Q000254:growth & development; D014796:Visual Perception / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; C096445:tim protein, Drosophila