Biology subjects

Gajdos, T.

Publications and source records attributed to Gajdos, T..

5 recordsLinked to original sources

bioRxiv2025

A myofilament lattice model of Drosophila flight muscle sarcomeres based on multiscale morphometric analysis during development

The indirect flight muscle is a widely used model for studying sarcomere structure and muscle development due to its extremely regular architecture. Nevertheless, precise measurement of the basic sarcomeric parameters remains a challenge even in this greatly ordered tissue. In this study, we identified several factors affecting measurement reliability and developed a software tool for precise, high-throughput measurement of sarcomere length and myofibril width. The accuracy of this new tool was validated against simulated images and blinded manual measurements. To extend the scope of this morphometric analysis to the sub-sarcomeric scale, we used electron and super-resolution microscopy to quantify myofilament number and filament length during myofibrillogenesis. These results provided novel insights into the dynamics of sarcomere growth, and enabled us to construct a refined model of sarcomere growth reaching to the level of individual myofilaments and providing a spatial framework for interpreting molecular localization data. These findings enhance our understanding of sarcomere assembly and offer a foundation for future studies of muscle development and function. SUMMARY STATEMENTThis study identifies factors influencing sarcomere size measurements, introduces a validated tool for precise analysis, and presents a comprehensive model of Drosophila flight muscle sarcomere growth during muscle development.

developmental biology↗

bioRxiv2025

Integrating explicit reliability for optimal choices: effect of trustworthiness on decisions and metadecisions

A key challenge in todays fast-paced digital world is to integrate information from various sources, which differ in their reliability. Yet, little is known about how explicit probabilistic information about the likelihood that a source provides correct information is used in decision-making. Here, we investigated how such explicit reliability markers are integrated and the extent to which individuals have metacognitive insight into this process. We developed a novel paradigm where participants viewed opinions from sources of varying reliability to make a choice between two options. After each decision, they rated how much they felt a given source influenced their choice. Using computational modelling, we estimated the effective reliability that participants assigned to each source and how leaky their decision process was. Overall, we found that participants acted as if sources were more informative than they actually were, inflating the reliability they were communicated. Interestingly, we show that even though sources were explicitly labelled as unreliable, these sources biased choices, as if these were treated as moderately reliable. Additionally, the presence of sources known to be lying, reliably voting for the incorrect answer, impaired performance by increasing decision leakiness. Despite these biases, participants showed some metacognitive awareness of what influenced their choices: they were generally accurate in reporting the degree to which a source influenced them and were aware of the impact unreliable sources had on their decisions. These results suggest that people make suboptimal use of explicit source reliability, but have some awareness of their suboptimal choices. Author summaryIn everyday life, we constantly draw on information from multiple sources that differ in how much they can be trusted. When scrolling through social media or online platforms, for instance, we know some sources are reliable, others dubious, and some clearly misleading. In this study, we created a simple task mirroring this everyday challenge to examine how people form beliefs using information from sources of known, varying reliability. Using a computational model, we uncovered two systematic ways in which decisions fell short of optimal. First, sources that were clearly identified as unreliable still influenced the opinions and final choice of individuals. Second, peoples choices were often swayed by the last piece of information they saw, especially in a context where misleading sources were present. Surprisingly, participants were aware of some of these biases and could report which sources had shaped their choices, suggesting that awareness of bias is not necessarily sufficient to overcome it.

neuroscience↗

bioRxiv2023

Action monitoring boosts perceptual confidence

Dominant models of metacognition suggest that sensory information quality determines perceptual confidence, but recent accounts propose that motor signals also affect confidence judgments. In this study, we investigated the impact of motor planning of perceptual responses on decision confidence, testing two hypotheses. The "fluency hypothesis" suggests that ease of motor response selection and preparation enhances confidence. In contrast, the "monitoring hypothesis" posits that increased action monitoring during response selection boosts confidence, potentially counteracting response fluency. In three pre-registered experiments, participants reported the orientation of a stimulus and indicated their confidence in their response. A cue induced action planning that was either congruent or incongruent with the response side used to report the stimulus orientation. Across experiments, we consistently observed higher confidence when participants prepared spatially incongruent actions compared to congruent ones, regardless of response accuracy. In the third experiment, electroencephalography (EEG) revealed an increased fronto-central P2 amplitude for incongruent actions, suggesting that incongruent action planning heightened early attentional resources needed to resolve response conflict. Incongruent action plans also modulated post-response ERPs at centro-parietal channels (e.g., Pz), typically linked to confidence and error monitoring. These findings align with the "monitoring hypothesis" suggesting that the degree of action monitoring during response selection modulates retrospective decision confidence. Public Significance StatementWhile virtually every decision we make leads to an action, the role of motor processes in decision making has been largely neglected. Our results show that retrospective confidence in a perceptual discrimination task is boosted when the motor execution is spatially incongruent with motor preparation, independently of the correctness of the response. Electroencephalography recordings indicate that this effect could be explained by a larger involvement of early attentional resources related to action monitoring, which has an impact on confidence computations. Taken together, these results suggest that action planning information might trigger monitoring mechanisms susceptible to alter retrospective confidence in our decisions, implying that motor processes are not only the output, but also an input of the decision mechanisms.

neuroscience↗

bioRxiv2023

High-intensity physical activity enhances cognitive decision processes

This study investigates the acute impact of high-intensity activity on perceptual decision-making, using computational modeling to assess changes during and after physical activity. Participants performed a two-alternative forced choice perceptual decision-making task at rest (pre- and post-exercise) and during six of eight 5-minute cycling bouts (totaling 47 minutes) under dual-task condition, while maintaining an average intensity of 86 {+/-} 7% of their maximum heart rate. Drift diffusion modeling was applied to accuracy and reaction time data to estimate changes in evidence accumulation (drift rate), decision threshold (boundary separation), and non-decision processes (ter). Results revealed improved post-exercise performance, characterized by shorter non-decision time, potentially reflecting a transient improvement in motor or perceptual efficiency. During ongoing physical activity, results indicate that exercise is associated with a decrease in non-decision time and an increase in the efficiency of evidence accumulation, while response caution remains stable. These findings provide novel insights into how sustained high-intensity exercise modulates perceptual decision-making dynamics under physiological stress.

neuroscience↗

bioRxiv2018

Impact of Physical and Cognitive Exertion on Cognitive Control

In a recent study, the differential effects of prolonged physiologically challenging 4 exercise upon two executive processes (cognitive control and working memory) have been 5 investigated. However, the impact of exercise on the selective inhibition task remained debatable and needed further analysis to dissociate the effects induced by exercise intensity from those induced by the time spent on task upon cognitive control outcomes. In this study we propose a thorough analysis of these data, using a generalized mixed model on a trial-by-9 trial basis and a new measure of the strength of the automatic response based on reaction time distribution, to disentangle the effect of physical fatigue from cognitive fatigue. Despite the prolonged duration of exercise, no decline in cognitive performance was found in response to physical fatigue. The only change observed over the 60-min exercise was an acceleration of the correct trials and an increase of errors for incompatible trials. This pattern, similar in both exercise conditions, supports the occurrence of cognitive fatigue induced by the repetition of the cognitive tasks over time.

neuroscience↗