Biology subjects

Pierzchlinska, A.

Publications and source records attributed to Pierzchlinska, A..

3 recordsLinked to original sources

bioRxiv2026

Role of leg campaniform sensilla sensory feedback in Drosophila melanogaster adaptive walking

With the newly uncovered access to a genetic line labeling all campaniform sensilla in Drosophila melanogaster and the many insights gathered from larger insects, we analyzed the distribution and patterning of this class of proprioceptors throughout the fly nervous system and studied CS function in motor control. We demonstrate via two-photon calcium imaging microscopy that campaniform sensilla activation induces activity in many leg muscles, showing that these proprioceptive stimuli can influence motor neuron activity. We then dissected how the lack of these proprioceptive stimuli influence walking behavior, leg kinematics, and interleg coordination in freely-walking flies using transient optogenetic inhibition and video tracking with high spatiotemporal resolution. We show that CS inhibition robustly affects Drosophila melanogasters ability to reach their typical walking speeds. Detailed analysis of leg kinematic suggests that shorter stance amplitudes characterized by their long-lasting duration were behind the speed deficits. Dissecting this phenotype also revealed the inability to maintain coordinated interleg stepping patterns as well as postural control in absence of proprioceptive force and load feedback.

neuroscience↗

bioRxiv2025

The TRP-channel painless mediates substrate stiffness sensing in the legs during Drosophila oviposition

The distinct textural properties of fruits in varying stages of ripening present unique ecological opportunities for several species of fruit flies, resulting, over evolutionary times, in specialized egg-laying behaviors. In this study we identified a TrpA channel-dependent mechanosensory pathway in the legs, through the gene painless, that modulates the discernment of softer patches for oviposition in gravid D. melanogaster females. We report that the stiffness-sensing role of tarsi is mediated through external sensory organs housed, namely ventral mechanosensory bristles and subsets of campaniform sensilla present primarily at the joints between tarsomeres. Our findings provide new evidence that campaniform sensilla function as indirect stiffness sensors of oviposition substrates, owing to their placement at joints that experience maximal cuticular distortion. We show that Painless is expressed in mechanosensory neurons innervating peripheral organs where it likely participates in the transduction of stiffness-evoked stimuli. Furthermore, we observed that overexpression of painless in both campaniform sensilla and mechanosensory bristles partially rescues preference for the softer substrates in painless mutants, indicating that painless activity in these organs is necessary to mediate the preference. We propose that different interactions with a soft vs. a hard substrate (compression of the cuticle, distribution of contacts) results in differential mechanotransduction in painless-expressing neurons, determining oviposition preferences.

neuroscience↗

bioRxiv2025

Avoidance engages dopaminergic punishment in Drosophila

It was classically suggested that behaviour can cause emotions (Darwin 1872). For example, smiling can make us feel happier, and in rodents the induced patterns of cardiac activity and breathing that are indicative of fear can in turn evoke it (Coles et al. 2022, Hsueh et al. 2023, Jhang et al. 2024). However, the adaptive significance of such feedback is unclear. We show that inducing backward movement, an element of avoidance behaviour in Drosophila, engages negative valence signals in these animals, and reveal the neuronal mechanisms and adaptive significance of this effect. We develop a paradigm with odours as conditioned stimuli paired with optogenetically induced backward movement instead of a punishing unconditioned stimulus, and combined these experiments with pharmacology, high-resolution video tracking, functional imaging, connectome analyses, and modelling. Our results show that backward movement engages dopaminergic punishment neurons and supports aversive memories. Such avoidance-to-punishment feedback counterbalances extinction learning and maintains learned avoidance, reducing the risk of further punishment. This can explain the long-standing "avoidance paradox", the observation that avoidance adaptively persists even when it is successful and no punishment is received (Bolles 1972). Our results provide a neurobiologically grounded argument for an integrated view of behaviour organization and valence processing.

neuroscience↗