Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Adishthi S Gurav
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Tyler H Ogunmowo
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Hannah Hackbart
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Ahmed Elsheikh
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Andrew A Verdegaal
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
One output arm of the sleep homeostat in Drosophila appears to be a group of neurons with projections to the dorsal fan-shaped body (dFB neurons) of the central complex in the brain. However, neurons that regulate the sleep homeostat remain poorly understood. Using neurogenetic approaches combined with Ca2+ imaging, we characterized synaptic connections between dFB neurons and distinct sets of upstream sleep-regulatory neurons. One group of the sleep-promoting upstream neurons is a set of circadian pacemaker neurons that activates dFB neurons via direct glutaminergic excitatory synaptic connections. Opposing this population, a group of arousal-promoting neurons downregulates dFB axonal output with dopamine. Co-activating these two inputs leads to frequent shifts between sleep and wake states. We also show that dFB neurons release the neurotransmitter GABA and inhibit octopaminergic arousal neurons. We propose that dFB neurons integrate synaptic inputs from distinct sets of upstream sleep-promoting circadian clock neurons, and arousal neurons.
