A neural switch for temperature-adaptive sleep behaviors in Drosophila

Abstract

Genes and neural circuits coordinate their elaborative activity to sustain sleep homeostasis. However, it remains elusive how these endogenous factors shape animal sleep in response to environmental changes. Here we demonstrate that synaptic plasticity in GABA transmission onto sleep-promoting dorsal fan-shaped body (dFSB) neurons acts as a neural mechanism important for temperature-adaptive behavioral plasticity in Drosophila sleep. At lower temperatures, opposing effects between the voltage-gated potassium channel Shaker in GABAergic neurons and the ionotropic GABA receptors in dFSB neurons primarily set the duration of daytime sleep. While GABA transmission suppresses cAMP signaling downstream of the constitutively active dopaminergic synapses on dFSB neurons, higher temperatures down-scale the presynaptic GABA transmission, thereby potentiating dopamine transmission in dFSB neurons. Temperature-depend switching. between these two synaptic modalities establishes a flip-flop model, which may adaptively tune the neural activity of dFSB neurons to temperature shifts and reorganize sleep architecture to the benefit of animal fitness.