Biology subjects

Mussini, E.

Publications and source records attributed to Mussini, E..

3 recordsLinked to original sources

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

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↗

bioRxiv2023

The interplay between focus of attention, respiratory phases, and the Heartbeat Evoked Potential

The Heartbeat Evoked Potential (HEP) is an EEG fluctuation that reflects the cortical processing of cardiac signals. HEP amplitude increases during various tasks involving cardiac interoception. Recent research has also indicated that HEP amplitude and cardiac interoceptive accuracy are higher during exhalation compared to inhalation. This difference may be due to the suppression of heartbeat-related sensations during inhalation and the amplification of sensations during exhalation through attentional mechanisms. Despite significant advancements in HEP research, the interactions between the HEP, interoceptive attention, and respiration are still unclear. In this study, we developed a novel experimental paradigm to investigate the relationship between HEP amplitude and respiratory phases during tasks that involve attention to cardiac interoception, non-cardiac interoception (specifically, respiration), and exteroceptive stimuli. The tasks included the Heartbeat Counting Task and the Breath Counting Task as interoceptive tasks, as well as the Cardiac-Tone Counting Task and the Breath-Tone Counting Task as exteroceptive tasks. Results demonstrated significant increases in HEP amplitude during the Heartbeat Counting Task compared to the Cardiac-Tone Counting Task and the Breath Counting Task, mostly observed over fronto-central electrodes in a late time-window. Notably, the amplitude increases during the Heartbeat Counting Task were primarily driven by HEPs recorded during exhalation, while inhalation had minimal impact. These findings align with the predictive coding model of interoceptive perception, suggesting that HEP amplitude reflects a precision-weighting process of prediction errors related to cardiac sensations that is specifically influenced by attention directed toward the heart. Furthermore, our findings emphasize the crucial role of exhalation in this precision-weighting process. These results may have considerable implications for the development of respiratory interventions to fine-tune cardiac interoception.

neuroscience↗