Biology subjects

Thane, M.

Publications and source records attributed to Thane, M..

3 recordsLinked to original sources

bioRxiv2026

Starvation modulates associative short-term memory of Drosophila in a task-dependent manner

It is widely believed that starvation favours the processing of food-related cues, a notion here called the adaptive specificity hypothesis. Indeed, in Drosophila melanogaster starvation is required for appetitive odour-sugar but not for aversive odour-shock memory. Results from Gruber et al. (2013) and Meschi et al. (2024), however, suggest that starvation improves aversive short-term memory, too, challenging this hypothesis. We survey how starvation affects Drosophila associative olfactory short-term memory across 26 learning tasks. These tasks differ in the reinforcers and the amount of training, the life stage of the animals, in the predictive structure and associative timing of the task, in whether memory is expressed as an increase or decrease in odour preference, and in whether the learned behaviour is motivated by obtaining reward or avoiding/ escaping punishment. In adult flies, an improvement was observed for appetitive odour-sugar memories, whereas all tasks yielding aversive memory were unaffected. Strikingly, appetitive tasks that are not sugar-related, namely odour-shock extinction learning and punishment-relief associations, were either unaffected or even impaired, supporting the adaptive specificity hypothesis. In contrast, in 5-day-old larvae sugar-related appetitive associations were compromised, and the same was observed, to varying degrees, in larvae starved one day earlier and for aversive quinine associations, challenging the adaptive specificity hypothesis. Furthermore, we observed starvation-induced changes in locomotion and preference for a subset of the cues used in our study. Our results defy a simplistic interpretation in terms of the adaptive specificity hypothesis and call for case-by-case analyses of how starvation affects learning and behaviour.

neuroscience↗

bioRxiv2023

Intron retention of an adhesion GPCR generates single transmembrane-helix isoforms to enable 7TM-adhesion GPCR function

Adhesion G protein-coupled receptors (aGPCR) function as metabotropic mechanosensors in the nervous system and other organs. aGPCR are heavily spliced forecasting an extraordinary molecular structural diversity. Many predicted isoforms lack the transmembrane (7TM) signaling subunit, but to what extent these non-GPCR isoforms are produced and what physiological purpose they serve is unknown. Alternative splicing through intron retention of ADGRL/Latrophilin/Cirl mRNA in Drosophila generates transcripts encoding unconventional proteins with an extracellular domain anchored by a single transmembrane helix (Cirl1TM). Here, we show that Cirl1TM transcripts are translated in vivo and that Cirl1TM binds Cirl7TM N-terminal fragment-dependently. This interaction enables mechanosensory neurons to distinguish input intensities through Go-dependent signaling. Similarly, a direct interaction was found for mammalian GPR126/ADGRG6 isoforms. Together, our findings define intron retention and isoform-specific heteromerization as extraordinary molecular strategies to adjust Cirl-dependent mechanosensation and demonstrate physiological relevance of versatile aGPCR isoform repertoire to tune cellular responsiveness.

neuroscience↗

bioRxiv2022

High-resolution analysis of individual Drosophila melanogaster larvae within groups uncovers inter- and intra-individual variability in locomotion and its neurogenetic modulation

Neuronally orchestrated muscular movement and locomotion are defining faculties of multicellular animals. Due to its numerically simple brain and neuromuscular system and its genetic accessibility, the larva of the fruit fly Drosophila melanogaster is an established model to study these processes at tractable levels of complexity. However, although the faculty of locomotion clearly pertains to the individual animal, present studies of locomotion in larval Drosophila mostly use group assays and measurements aggregated across individual animals. The alternative is to measure animals one at a time, an extravagance for larger-scale analyses. In principle or in practice, this in particular rules out grasping the inter- and intra-individual variability in locomotion and its genetic and neuronal determinants. Here we present the IMBA (Individual Maggot Behaviour Analyser) for tracking and analysing the behaviour of individual larvae within groups. Using a combination of computational modelling and statistical approaches, the IMBA reliably resolves individual identity across collisions. It does not require specific hardware and can therefore be used in non-expert labs. We take advantage of the IMBA first to systematically describe the inter- and intra-individual variability in free, unconstrained locomotion in wild-type animals. We then report the discovery of a novel, complex locomotion phenotype of a mutant lacking an adhesion-type GPCR. The IMBA further allows us to determine, at the level of individual animals, the modulation of locomotion across repeated activations of dopamine neurons. Strikingly, IMBA can also be used to analyse silly walks, that is patterns of locomotion it was not originally designed to investigate. This is shown for the transient backward locomotion induced by brief optogenetic activation of the brain-descending mooncrawler neurons, and the variability in this behaviour. Thus, the IMBA is an easy-to-use toolbox allowing an unprecedentedly rich view of the behaviour and behavioural variability of individual Drosophila larvae, with utility in multiple biomedical research contexts.

neuroscience↗