A wake-active locomotion circuit depolarizes a sleep-active neuron to switch on sleep

• DOI: 10.1371/journal.pbio.3000361
• Publication Date: 2020-02-20T18:31:12Z
• Authors: Elisabeth Maluck; Inka Busack; Judith Besseling; Florentin Masurat; Michal Turek; Karl Emanuel Busch; Henrik Bringmann
• Keywords: Sleep

Sleep-active neurons depolarize during sleep to suppress wakefulness circuits. Wake-active wake-promoting in turn shut down sleep-active neurons, thus forming a bipartite flip-flop switch. However, how is switched on unclear because it not known translated into neuron depolarization when the system set sleep. Using optogenetics Caenorhabditis elegans, we solved presynaptic circuit for of RIS developmentally regulated sleep, also as lethargus. Surprisingly, found that activation requires have roles and locomotion behavior. The RIM interneurons—which are active can induce reverse locomotion—play complex role act inhibitors they strongly depolarized activators modestly depolarized. PVC command interneurons, which promote forward wakefulness, major RIS. properties these modulated RIMs become less excitable. PVCs resistant inhibition an increased capacity activate Separate neither nor appears be sufficient induction; instead, our data suggest concert Forward activity normally mutually exclusive. Our may activated at transition between states, perhaps both (PVC) (including RIM) overlap. While outside lethargus, altered interneurons lethargus favors strong control by circuits suggests evolved from control. switch C. elegans additional component, wake-active sleep-promoting translate worm sleepy. required state switching other animals, including mammals.