Sleep promoting neurons remodel their response properties to calibrate sleep drive with environmental demands.

Abstract

Falling asleep at the wrong time can place an individual at risk of immediate physical harm. However, not sleeping degrades cognition and adaptive behavior. To understand how animals match sleep need with environmental demands, we used live-brain imaging to examine the physiological response properties of the Drosophila sleep homeostat (dFB) following interventions that modify sleep (sleep deprivation, starvation, time-restricted feeding, memory consolidation). We report that dFB neurons can distinguish between different types of waking and can change their physiological response-properties accordingly. That is, dFB neurons are not simply passive components of a hard-wired circuit. Rather, the dFB neurons themselves can determine their response to the activity from upstream circuits. Finally, we show that the dFB appears to contain a memory trace of prior exposure to metabolic challenges induced by starvation or time-restricted feeding. Together these data highlight that the sleep homeostat is plastic and suggests an underlying mechanism.

Metabolically driven action potentials serve neuronal energy homeostasis and protect from reactive oxygen species

“…Kempf et al 18 show that the production of RETROS over the course of a day in the dorsal fan-shaped body (dfb) neurons of fruit flies is correlated with their increased firing, and consequent sleep onset. Finally, Dissel and colleagues show 19 that dfb neurons keep a memory trace of recent metabolic challenges to promote wakefulness, although the pertinence of RETROS was not directly addressed here.…”