Biology subjects

Candidi, M.

Publications and source records attributed to Candidi, M..

7 recordsLinked to original sources

bioRxiv2025

Integrating multiple sensory modalities during dyadic interactions drives self-other differentiation at the behavioral and electrocortical level

Interpersonal motor interactions represent a key setting for processing signals from multiple sensory channels simultaneously, possibly modulating cross-modal multisensory integration, that is a crucial perceptual mechanism where different sensory sources of information are combined into one single percept. Here we explored whether integrating sensorimotor signals while interacting with a partner can lead to shared sensorimotor representations, and possibly to a recalibration of individuals multisensory perception. In detail, we investigated whether engaging individuals in dyadic activities that utilized either single (e.g., visual or tactile/proprioceptive) or combined (e.g., visuo-tactile/proprioceptive) sensory modalities would impact the behavioral and electrocortical markers associated with interpersonal cross-modal integration. We show that interactions requiring the integration of multiple sensory modalities lead to higher interpersonal differentiation resulting in reduced interpersonal cross-modal integration in a subsequent spatial detection task and alter its distributed neural representations. Specifically, the neural patterns elicited by interpersonal visuo-tactile stimuli vary based on the sensory nature of the previous interpersonal interaction, with the one involving multiple sensory modalities resulting in improved performance of a neural classifier. These findings suggest new avenues for sensorimotor approaches in social neuroscience, emphasizing the malleability of self-other representations based on the nature of interpersonal interactions. SIGNIFICANCE STATEMENTSuccessful social interaction relies on the dynamic integration of sensory and motor signals between individuals. Here, we show that the sensory channels engaged during interpersonal coordination recalibrate how the brain processes multisensory information about the self and others after having interacted with them. Specifically, interactions involving integrated visual and proprioceptive feedback sharpen self-other distinction and reduce cross-modal interference. These effects manifest in both behavioral responses and early neural activity patterns, revealing plastic, offline changes in multisensory integration shaped by social sensorimotor contingencies. Our findings highlight the role of interpersonal experience in shaping the functional responses to multisensory stimuli and provide novel insights into the sensorimotor foundations of social embodied cognition.

neuroscience↗

bioRxiv2024

Dopaminergic modulation of behavioral and electrocortical markers of interpersonal performance monitoring in Parkinson's Disease: insights from multivariate and univariate analyses

Effective interpersonal interaction necessitates constant monitoring and adaptation to others actions, a process known as interpersonal performance monitoring, which is influenced by the dopaminergic system and marked by specific electrocortical signatures. To explore the connection between deficits in interpersonal performance monitoring and altered neural markers, we assessed patients with Parkinsons Disease (PD) performing coordination tasks with a virtual partner (VP) under two conditions: on dopaminergic medication (PD ON) and after withdrawal (PD OFF). In Interactive trials, which required adaptation to the VPs actions, PD OFF performance was impaired compared to PD ON. EEG analysis revealed in PD OFF increased midfrontal Delta-Theta activity during Interactive trials. Higher Delta-Theta synchronization was associated with improved performance, suggesting compensatory mechanisms. Multivariate EEG analysis distinguished Interactive from Cued trials, especially in PD OFF. Our findings highlight dopamine s role in modulating electrocortical markers of interpersonal performance monitor, with significant implications for understanding and treating PD.

neuroscience↗

bioRxiv2024

The bodily appearance of a virtual partner affects the activity of the action observation and action monitoring systems in a minimally interactive task

One pending question in social neuroscience is whether interpersonal interactions are processed differently by the brain depending on the bodily characteristics of the interactor, i.e., their physical appearance. To address this issue, we engaged participants in a minimally interactive task with an avatar either showing bodily features or not while recording their brain activity using Electroencephalography (EEG) in order to investigate indices of action observation and action monitoring processing. Multivariate results showed that bodily compared to non-bodily appearance modulated parieto-occipital neural patterns throughout the entire duration of the observed movement and that, importantly, such patterns differ from the ones related to initial shape processing. Furthermore, among the electrocortical indices of action monitoring, only the early observational Positivity (oPe) was responsive to the bodily appearance of the observed agent under the specific task requirement to predict the partner movement. Taken together, these findings broaden the understanding of how bodily appearance shapes the spatiotemporal processing of an interactors movements. This holds particular relevance in our modern society, where human-virtual agent interactions are rapidly becoming ubiquitous.

neuroscience↗

bioRxiv2022

Early categorization of social affordances during the visual encoding of bodily stimuli

Interpersonal interactions rely on various communication channels, both verbal and non-verbal, through which information regarding ones intentions and emotions are perceived. Here, we investigated the neural correlates underlying the visual processing of hand postures conveying social affordances (i.e., hand-shaking), compared to control stimuli such as hands performing non-social actions (i.e., grasping) or showing no movement at all. Combining univariate and multivariate analysis on electroencephalography (EEG) data, our results indicate that occipito-temporal electrodes show early differential processing of stimuli conveying social information compared to non-social ones. First, the amplitude of the Early Posterior Negativity (EPN, an Event-Related Potential related to the perception of body parts) is modulated differently during the perception of social and non-social content carried by hands. Moreover, our multivariate classification analysis (MultiVariate Pattern Analysis - MVPA) expanded the univariate results by revealing early (<200ms) categorization of social affordances over occipito-parietal sites. In conclusion, we provide new evidence suggesting that the encoding of socially relevant hand gestures is categorized in the early stages of visual processing.

neuroscience↗

bioRxiv2021

Midfrontal theta tACS facilitates motor coordination in dyadic human-avatar motor interactions

Synchronous interpersonal motor interactions require moment-to-moment predictions and proactive monitoring of the partners actions. Neurophysiologically, this is highlighted by an enhancement of midfrontal theta activity. In the present study we explored the causal role of midfrontal theta for interpersonal motor interactions employing transcranial alternating current stimulation (tACS). We implemented a realistic human-avatar interaction task in immersive virtual reality (IVR) where participants controlled a virtual arm and hand to press a button synchronously with a virtual partner. Participants completed the task while receiving theta (Experiment 1) or beta (control frequency, Experiment 2) EEG-informed tACS over the frontal midline, as well as sham stimulation as a control. Results showed that frontal theta tACS significantly improved behavioural performance (by reducing interpersonal asynchrony) and participants motor strategies (by increasing movement times and reducing reaction times), while beta tACS had no effect on these measures. These results suggest that theta tACS over frontal areas facilitates action monitoring and motor abilities supporting interpersonal interactions.

neuroscience↗

bioRxiv2021

The monitoring system is attuned to others' actions during dyadic motor interactions

Successful interpersonal motor interactions necessitate the simultaneous monitoring of our own and our partners actions. To characterize the dynamics of the action monitoring system for tracking self and other behaviors during dyadic synchronous interactions, we combined EEG recordings and immersive Virtual Reality in two tasks where participants were asked to coordinate their actions with those of a Virtual Partner (VP). The two tasks differed in the features to be monitored: the Goal task required participants to predict and monitor the VPs reaching goal; the Spatial task required participants to predict and monitor the VPs reaching trajectory. In both tasks, the VP performed unexpected movement corrections to which the participant needed to adapt. By comparing the neural activity locked to the detection of unexpected changes in the VP action (other-monitoring) or to the participants action-replanning (self-monitoring), we show that during interpersonal interactions the monitoring system is more attuned to others than to ones own actions. Additionally, distinctive neural responses to VPs unexpected goals and trajectory corrections were found: goal corrections were reflected both in early fronto-central and later posterior neural responses while trajectory deviations from the expected movement were reflected only in later and posterior responses. Since these responses were locked to the partners behavior and not to ones own, our results indicate that during interpersonal interactions the action monitoring system is dedicated to evaluating the partners movements. Hence, our results reveal an eminently social role of the monitoring system during motor interactions. Significance StatementNon-verbal synchronous interpersonal interactions require the monitoring of both our actions and those of our partners. Understanding the neural underpinnings of this ability with a focus on the dynamics between self- and other-monitoring is fundamental to the comprehension of social coordination. By combining EEG and immersive Virtual Reality we demonstrate that the monitoring system is more attuned to others actions than to our own. In two tasks, we show that the neural activity associated with unexpected corrections in the goal or the trajectory of an action are locked to the partners actions rather than to the participants subsequent adaptation. This pattern of results highlights a social mode adopted by the monitoring system to handle motor interactions.

neuroscience↗

bioRxiv2018

Frontal and occipito-temporal Theta activity as marker of error monitoring in Human-Avatar joint performance.

Discrepancies between sensory predictions and action outcome are at the base of error coding. However, these phenomena have mainly been studied focusing on individual performance. Here, we explored prediction errors during a human-avatar motor interaction and focused on both the classical frontal error-related brain responses and the activity of the action observation network. Our motor interaction paradigm required healthy individuals to synchronize their reach-to-grasp movements with those of a virtual partner in conditions that did (Interactive) or did not require (Cued) movement prediction and adaptation to the partners actions. Crucially, in 30% of the trials the virtual partner suddenly and unpredictably changed its movement trajectory thereby violating the human participants expectation. These changes elicited error-related neuromarkers (ERN/Pe - Theta/Alpha modulations) over fronto-central electrodes mainly during the Interactive condition. Source localization and connectivity analyses showed that the frontal Theta activity induced by violations of the expected interactive movements was in phase with occipito-temporal Theta activity. These results expand current knowledge about the neural correlates of on-line motor interactions linking the frontal error-monitoring system to visual, body motion-related, responses.

neuroscience↗