Biology subjects

Sinigaglia, C.

Publications and source records attributed to Sinigaglia, C..

10 recordsLinked to original sources

bioRxiv2025

Rational Expectations and Kinematic Information in Coordination Games

Successful coordination often requires integrating strategic reasoning with real-time observations of others actions, yet how humans resolve conflicts between these information sources remains unclear. This study aimed to fill this gap by examining how people coordinate in a strategic game when observing partial kinematic information from their partners actions. Participants played a HI-LO game with a virtual partner, choosing payoffs based on grasping movements toward invisible large and small targets. Hand movements were presented as schematic animations, with partners grasping targets linked to higher or lower payoffs across two configurations. Participants relied exclusively on kinematic cues from hand shape changes in maximum grip aperture to infer their partners choices. There were two main findings. While participants preferred higher payoffs consistent with rational game-theoretic expectations, reliable kinematic cues overrode these expectations. When early grip aperture changes indicated the partner was reaching for a large target associated with a lower payoff, participants abandoned their default preference for higher payoffs. They chose the lower option instead, achieving a high coordination success rate. These findings demonstrate that people prioritize kinematic cues about others choices over theoretical assumptions about rational behavior when coordinating. This suggests that movement-based inferences about others actions in natural social interactions may be weighted more heavily than strategic reasoning when the two sources of information conflict.

neuroscience↗

bioRxiv2025

ACTION ENHANCEMENT DRIVES THE EMBODIMENT OF A SUPERNUMERARY ROBOTIC DIGIT

Wearable robotic supernumerary limbs enhance motor capabilities by leveraging principles from both engineering and neuroscience. Despite extensive research, how supernumerary limbs become embodied and the relationship between embodiment and artificially enhanced action possibilities remain largely unexplored. This gap has implications for device design and clinical adoption, as embodiment likely promotes patients acceptance and daily use of their supernumerary limb. Using an adapted proprioceptive drift paradigm from rubber hand illusion research, we investigated the embodiment of a robotic Soft Sixth Finger (SSF). Participants performed grasp-to-lift actions versus mere lift actions without object interaction, wearing the SSF on two different configurations: the palm and back of the hand. The Palm condition involved achievable actions without the SSF, while the Dorsal condition enabled otherwise anatomically impossible actions, extending beyond the physiological motor repertoire. Hand proprioceptive drift was measured before and after each task. Results showed that the SSF impacted body representation only when dorsally mounted. Proprioceptive drift was significantly higher for grasp-to-lift actions in Dorsal versus Palm conditions and higher for grasp-to-lift versus mere lift in the Dorsal condition only. This proves that SSF embodiment relates to extending, rather than substituting, users action possibilities. Future research must integrate behavioral, cognitive, and neural measurements across healthy and patient populations. Our study provides an ideal model for clinical application, demonstrating how enabling otherwise impossible actions drives robotic supernumerary finger embodiment.

neuroscience↗

bioRxiv2025

EARLY TARGET PREDICTION IN ACTION OBSERVATION

Previous research has established that observers can predict action targets through hand preshaping. However, two critical questions remain unexplored: how predictions adapt to the available kinematic information and evolve throughout the movement timeline. We address these fundamental gaps by combining kinematic analysis with machine-learning approaches that differentiate between motor and visual cues. Using motion capture technology, we recorded reach-to-grasp actions toward large and small objects and had participants predict target size from hand kinematics at varying time points. Our analysis revealed that prediction performance not only evolved with increasing kinematic information but, crucially, differed significantly between target size choices. To provide insight into the underlying processes, we developed a comparative framework using two distinct machine learning approaches: Support Vector Machines (SVM) modeling kinematic information and CNN-RNN networks extracting visual patterns. The stronger alignment between human performance and SVM predictions offers empirical evidence that kinematic cues, rather than visual patterns, mostly guide target prediction. These findings advance our understanding of action prediction and have significant implications for social cognition and human-machine interaction. PUBLIC SIGNIFICANCE STATEMENTUnderstanding others intentions by observing their hand movements is crucial for social interaction, from passing objects to coordinating complex tasks. This study reveals that people use different cues to predict whether someone is reaching for a large versus a small object from the earliest stages of hand movement. By comparing human performance with Artificial Intelligence models, we found that people primarily rely on motor cues to make these predictions. These insights could improve rehabilitation techniques for individuals with social interaction difficulties and enhance the design of intuitive robotic assistants.

neuroscience↗

bioRxiv2025

The SAFE Labs Handbook: community-driven commitments for group leaders to improve lab culture

Creating positive and equitable lab environments has become a growing priority for the scientific community and funders of scientific research. Research institutions typically respond to this need by providing mandatory or optional training opportunities for their staff. However, there is no established resource for group leaders to improve their lab culture with concrete action points for implementation. Here, we introduce the SAFE Labs Handbook: a collection of thirty "commitments" which can be verifiably actioned without requiring institutional support. These commitments were collaboratively developed by thirteen group leaders in life sciences, from institutions across eight countries, instigated through the 2024 SAFE Labs workshop. The importance of each commitment has been scored by more than 200 researchers, at various career stages, from more than twenty countries. Even though all commitments were rated as significantly important by scientists from all career stages, implementation rates were notably low (< 25%). Lab members reported higher importance scores than group leaders, with large divergences indicating where group leaders may underestimate the potential impact on lab culture. Indeed, the overall implementation rate was correlated with importance score for group leaders, but not lab members. Strikingly, more than 95% of group leaders said they would consider implementing the handbook commitments. Given the high importance-scores and low-implementation rates, the SAFE Labs Handbook represents a unique, community-driven tool with significant potential to improve lab culture on a global scale.

scientific communication and education↗

bioRxiv2025

How Acting Jointly Differs from Acting Side-by-Side: A Dual EEG Study

The distinction between acting jointly and acting side by side permeates our daily lives and is crucial for understanding the evolution and development of human sociality. While acting in parallel involves agents pursuing individual goals, acting jointly requires them to share a collective goal. Here, we used a dual electroencephalography (EEG) approach to explore the neural dynamics underlying joint and parallel action preparation. We recorded event-related potentials (ERPs) from 20 dyads while they had to transport an object in a video game, either jointly or in parallel, or individually. Both conditions were carefully matched for coordination demands and performance complexity, as confirmed by equal success rates. Our results revealed a distinctive pattern swap in ERPs during action preparation. In the early preparation phase, ERPs showed significantly higher amplitude during joint action than parallel action. This pattern reversed in the late preparation phase, with significantly reduced ERP amplitude in the joint compared to parallel action. Notably, the decrease in late ERPs correlated with higher reaction time (RT) variability in partners but not with participants own RT variability. The dynamic swap in neural activity suggests that different cognitive processes operate at distinct stages of action preparation. While initially sharing a collective goal may impose cognitive costs (reflected in higher early ERPs), this is offset by facilitated late action preparation, likely due to enhanced predictability of partners actions. Significance StatementOur study reveals distinct neural signatures differentiating joint from side-by-side actions. Through dual EEG recordings of twenty dyads performing complexity-matched tasks, we identified a distinctive "swap" in event-related potentials during action preparation. Joint actions initially showed higher early-phase amplitudes but significantly reduced late-phase amplitudes compared to parallel actions. Notably, this late-phase reduction correlated specifically with the variability of partners behavior. This suggests that sharing collective goals initially requires cognitive resources but facilitates action preparation through enhanced predictability of partners. These findings provide a neural framework for understanding the distinction between acting jointly and acting in parallel --a distinction that pervades our daily experiences and is crucial for understanding the development and evolution of human sociality.

neuroscience↗

bioRxiv2024

DOES EXPERIENCE MODULATE AUTOMATIC IMITATION? A NEW LOOK

Automatic imitation is a stimulus-response compatibility effect wherein observing an action automatically influences motor performance. However, the mechanism underlying this effect remains controversial. Associative Sequence Learning suggests that automatic imitation arises from contingent visual and motor activity associations. Prior studies have shown that exposure to counter-imitative training can alter these visuomotor associations, suggesting that automatic imitation can be modulated by experience. Here, we aim to bring new insight into how this modulation occurs by exploring the time course of automatic imitation before and after counter-imitative training. If automatic imitation is merely a result of contingent associations, as previously suggested, the effect should consistently be modulated following such training. However, if this is not the case, automatic imitation is not, or not only, a matter of contingent association, at least not as currently understood.

neuroscience↗

bioRxiv2021

Distinct gene expression dynamics in developing and regenerating limbs

Regenerating animals have the ability to reproduce organs that were originally generated in the embryo and subsequently lost due to injury. Understanding whether the process of regeneration mirrors development is an open question in most regenerative species. Here we take a transcriptomics approach to examine to what extent leg regeneration shows the same temporal patterns of gene expression as leg development in the embryo, in the crustacean Parhyale hawaiensis. We find that leg development in the embryo shows stereotypic temporal patterns of gene expression. In contrast, global patterns of gene expression during leg regeneration show a high degree of variation, related to the physiology of individual animals. A major driver of this variation is the molting cycle. After dissecting the transcriptional signals of individual physiology from regeneration, we obtain temporal signals that mark distinct phases of leg regeneration. Comparing the transcriptional dynamics of development and regeneration we find that, although both processes use largely the same genes, the temporal patterns in which these gene sets are deployed are different and cannot be systematically aligned. HIGHLIGHTSO_LISingle-limb data on transcriptional dynamics of leg development and regeneration C_LIO_LIDeveloping embryonic legs show stereotypic transcriptional profiles C_LIO_LIRegenerating leg transcriptomes show a high degree on individual variation C_LIO_LIRegenerating leg transcriptomes are influenced by adult physiology, especially molting C_LIO_LIRegenerating leg transcriptomes reveal distinct phases of leg regeneration C_LIO_LILeg development and regeneration use overlapping sets of genes in different temporal patterns C_LI

developmental biology↗

bioRxiv2019

Pattern regulation in a regenerating jellyfish

Clytia hemisphaerica jellyfish, with their tetraradial symmetry, offer a novel paradigm for addressing patterning mechanisms during regeneration. Here we show that an interplay between mechanical forces, cell migration and proliferation allows jellyfish fragments to regain shape and functionality rapidly, notably by efficient restoration of the central feeding organ (manubrium). Fragmentation first triggers actomyosin-powered remodeling that restores body umbrella shape, causing radial smooth muscle fibers to converge around "hubs" which serve as positional landmarks. Stabilization of these hubs, and associated expression of Wnt6, depends on the configuration of the adjoining muscle fiber "spokes". Stabilized hubs presage the site of the manubrium blastema, whose growth is Wnt/{beta}-catenin dependent and fueled by both cell proliferation and long-range cell recruitment. Manubrium morphogenesis is modulated by its connections with the gastrovascular canal system. We conclude that body patterning in regenerating jellyfish emerges mainly from local interactions, triggered and directed by the remodeling process.

developmental biology↗

bioRxiv2018

The genome of the jellyfish Clytia hemisphaerica and the evolution of the cnidarian life-cycle

Jellyfish (medusae) are a distinctive life-cycle stage of medusozoan cnidarians. They are major marine predators, with integrated neurosensory, muscular and organ systems. The genetic foundations of this complex form are largely unknown. We report the draft genome of the hydrozoan jellyfish Clytia hemisphaerica and use multiple transcriptomes to determine gene use across life-cycle stages. Medusa, planula larva and polyp are each characterised by distinct transcriptome signatures reflecting abrupt life cycle transitions, and all deploy a mixture of phylogenetically old and new genes. Medusa specific transcription factors, including many with bilaterian orthologs, associate with diverse neurosensory structures. Compared to Clytia, the polyp-only hydrozoan Hydra has lost many of the medusa-expressed transcription factors, despite similar overall rates of gene content and sequence evolution. Absence of expression and gene loss among Clytia orthologs of genes patterning the anthozoan aboral pole, secondary axis and endomesoderm support simplification of planulae and polyps in Hydrozoa, including loss of bilateral symmetry. Consequently, although the polyp and planula are generally considered the ancestral cnidarian forms, in Clytia the medusa maximally deploys ancestral cnidarian-bilaterian transcription factor gene complexity.

evolutionary biology↗

bioRxiv2017

A safer, urea-based in situ hybridization method improves detection of gene expression in diverse animal species

In situ hybridization is a widely employed technique allowing spatial visualization of gene expression in fixed specimens. It has proven to be essential to our understanding of biological processes, including developmental regulation. In situ protocols are today routine in numerous laboratories, and although details might change, they all include a hybridization step, where specific antisense RNA or DNA probes anneal to the target nucleic acids strand. This step, in general, is carried out at high temperatures and in a denaturing solution, the hybridization buffer, commonly containing 50% (v/v) formamide. An important drawback is that hot formamide poses a significant health risk and so must be handled with great care.\n\nWe were prompted to test alternative hybridization solutions for in situ detection of gene expression in the medusa of the hydrozoan Clytia hemisphaerica, where traditional protocols caused extensive deterioration of the morphology and texture during hybridization, hindering observation and interpretation of results. Inspired by optimized protocols for Northern and Southern blot analysis, we substituted the 50% formamide with an equal volume of 8 M urea solution in the hybridization buffer. The new protocol yielded better morphologies and consistency of tissues, and also notably improved the resolution of the signal, allowing more precise localization of gene expression, as well as reduced staining at non-specific sites. Given the improved results using a less toxic hybridization solution, we tested the urea protocol on a number of other metazoans: two brachiopod species (Novocrania anomala and Terebratalia transversa) and the worm Priapulus caudatus, obtaining a similar reduction of aspecific probe binding. Overall, substitution of formamide by urea in in situ hybridization offers safer alternative protocols, potentially useful in research, medical and teaching contexts. We encourage other workers to test this approach on their study organisms, and hope that they will also obtain better sample preservation, more precise expression patterns and fewer problems due to aspecific staining, as we report here for Clytia medusae and Novocrania and Terebratalia developing larvae.

developmental biology↗