Biology subjects

Ertekin, D.

Publications and source records attributed to Ertekin, D..

3 recordsLinked to original sources

bioRxiv2019

{-}{-} Downregulation of a satiety signal from peripheral fat bodies improves visual attention while reducing sleep need in Drosophila .

Sleep is vital for survival. Yet, under environmentally challenging conditions such as starvation, animals suppress their need for sleep. Interestingly, starvation-induced sleep loss does not evoke a subsequent sleep rebound. Little is known about how starvation-induced sleep deprivation differs from other types of sleep loss, or why some sleep functions become dispensable during starvation. Here we demonstrate that downregulation of unpaired-2 (upd2, the Drosophila ortholog of leptin), is sufficient to mimic a starved-like state in flies. We use this genetically starved state to investigate the consequences of a starvation signal on visual attention and sleep in otherwise well-fed flies, thereby sidestepping the negative side-effects of undernourishment. We find that knockdown of upd2 in the fat body is sufficient to suppress sleep while also increasing selective visual attention and promoting night-time feeding. Further, we show that this peripheral signal is integrated in the fly brain via insulin-expressing cells. Together, these findings identify a role for peripheral tissue-to-brain interactions in the simultaneous regulation of sleep and attention, to potentially promote adaptive behaviors necessary for survival in hungry animals.\n\nAuthor SummarySleep is important for maintaining both physiological (e.g., metabolic, immunological, and developmental) and cognitive processes, such as selective attention. Under nutritionally impoverished conditions, animals suppress sleep and increase foraging to locate food. Yet it is currently unknown how an animal is able to maintain well-tuned cognitive processes, despite being sleep deprived. Here we investigate this question by studying flies that have been genetically engineered to lack a satiety signal, and find that signaling from fat bodies in the periphery to insulin-expressing cells in the brain simultaneously regulates sleep need and attention-like processes.

neuroscience↗

bioRxiv2018

Sleep regulates visual selective attention in Drosophila

Although sleep-deprivation is known to impair attention in humans and other mammals, the underlying reasons are not well understood, and whether similar effects are present in non-mammalian species is not known. We therefore sought to investigate whether sleep is important for optimising attention in an invertebrate species, the genetic model Drosophila melanogaster. We developed a high-throughput paradigm to measure visual attention in freely-walking Drosophila, using competing foreground/background visual stimuli. We found that whereas sleep-deprived flies could respond normally to either stimulus alone, they were more distracted by background cues in a visual competition task. Other stressful manipulations such as starvation, heat exposure, and mechanical stress had no effects on visual attention in this paradigm. In contrast to sleep-deprivation, providing additional sleep using the GABA-A agonist 4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridine-3-ol (THIP) did not affect attention in wild-type flies, but significantly improved attention in the learning mutant dunce. Our results reveal a key function of sleep in optimising attention processes in Drosophila, and establish a behavioural paradigm that can be used to explore the molecular mechanisms involved.\n\nSummary statementSleep deprivation specifically impairs visual selective attention in fruit flies, without affecting behavioural responses to simple visual stimuli.

animal behavior and cognition↗

bioRxiv2018

Innate visual preferences and behavioral flexibility in Drosophila

Visual decision-making in animals is influenced by innate preferences as well as experience. Interaction between hard-wired responses and changing motivational states determines whether a visual stimulus is attractive, aversive, or neutral. It is however difficult to separate the relative contribution of nature versus nurture in experimental paradigms, especially for more complex visual parameters such as the shape of objects. We used a closed-loop virtual reality paradigm for walking Drosophila flies to uncover innate visual preferences for the shape and size of objects, in a recursive choice scenario allowing the flies to reveal their visual preferences over time. We found that Drosophila flies display a robust attraction / repulsion profile for a range of objects sizes in this paradigm, and that this visual preference profile remains evident under a variety of conditions and persists into old age. We also demonstrate a level of flexibility in this behavior: innate repulsion to certain objects could be transiently overridden if these were novel, although this effect was only evident in younger flies. Finally, we show that a reward circuit in the fly brain, Drosophila neuropeptide F (dNPF), can be recruited to guide visual decision-making. Optogenetic activation of dNPF-expressing neurons converted a visually repulsive object into a more attractive object. This suggests that dNPF activity in the Drosophila brain guides ongoing visual choices, to override innate preferences and thereby provide a necessary level of behavioral flexibility in visual decision-making.

animal behavior and cognition↗