Biology subjects

Bertoni, T.

Publications and source records attributed to Bertoni, T..

7 recordsLinked to original sources

bioRxiv2026

A Unified Neurocomputational Framework for Closed-Loop Motor Control and Sense of Agency

Motor control relies on the closed-loop comparison of motor commands and sensory feedback to correct errors and adapt to perturbations. Relevant features must be selected from a rich stream of sensory inputs and bound to the appropriate motor commands. This process remains poorly understood. Closed-loop control is accompanied by the experience of causing the observed feedback, sense of agency (SoA). SoA grounds self-identification, and its impairment is associated with lower prosthesis acceptance and disorders like autism and schizophrenia. Like closed-loop motor control, it relies on comparing desired and observed action outcomes in fronto-parietal circuits. Yet, these two phenomena have been studied independently, leaving SoA without a functional meaning and disregarding subjective aspects in motor control models. We propose that SoA is the subjective correlate of selecting self-caused sensory features for closed-loop control. We tested this in a visuomotor task where SoA was manipulated through temporal delays and adaptation to spatial perturbations served as a proxy for closed-loop integration. Delays similarly modulated SoA and closed-loop integration, suggesting these may emerge from the same phenomenon. We modelled our results in a Bayesian framework in which self-causation probability is inferred from temporal congruence, jointly modulating SoA and the weight attributed to visual feedback.

neuroscience↗

bioRxiv2026

Inferring When to Act from Temporal Regularities

Adaptive behaviour often requires deciding when to act in the absence of an explicit sensory cue. While temporal expectations are known to optimize behaviour when anticipated events trigger responses, it remains unclear how learned temporal regularities are transformed into internally generated decisions. Here, we developed the Temporal Inference Task, a novel virtual reality paradigm designed to isolate this transformation. Participants repeatedly observed an identical visual sequence in which a virtual object approached their hand. On most trials, a brief tactile No-Go signal instructed them to withhold their response, whereas on the remaining trials its omission required them to respond. Because Go trials were never accompanied by an explicit cue, participants had to infer when the expected No-Go signal could no longer occur before initiating a response. Across blocks, the timing of the No-Go signal was systematically varied, allowing participants to learn distinct temporal regularities while Go trials remained physically identical. Participants systematically shifted their response timing according to the learned temporal regularities. This behavioural adaptation was accompanied by corresponding shifts in parietal alpha- and beta-band desynchronization, with steeper pre-response desynchronization consistently preceding faster responses. Together, these findings identify a candidate neural mechanism through which learned temporal regularities are transformed into internally generated decisions about when to act.

neuroscience↗

bioRxiv2024

Multisensory integration in Peripersonal Space indexes consciousness states in sleep and disorders of consciousness

Conscious experience encompasses not only the awareness of external objects, but also a phenomenal representation of the embodied subject of the experience. The latter is mediated by the integration of multisensory stimuli between the body and the environment, a process mediated by the Peripersonal Space (PPS) system. Here we thus tested the hypothesis that a neural marker of PPS representation may index the presence of conscious experience. Using high-density EEG in awake participants, we identified a "PPS index", characterized by high-beta oscillations in centroparietal regions during the integration of audiotactile stimuli presented near versus far from the body. We then examined this marker across two models of altered consciousness, i.e., sleep and disorders of consciousness. The PPS index persisted during dreaming and waking conscious states but was absent during dreamless, unconscious states. Moreover, the same index predicted behavioural measures of consciousness and clinical outcome in patients recovering from disorders of consciousness. These results suggest that multisensory integration within the PPS is tightly linked to the presence of conscious experience.

neuroscience↗

bioRxiv2024

Proprioception Impacts Body Perception in Healthy Aging: Insights from a Psychophysical and Computational Approach

The experience of owning a body (body ownership, BO) and the perception of our body dimensions (metric body representation, mBR) depend on the integration of multisensory cues. As the human sensory system is subjected to a decline along the lifespan, encompassing all sensory modalities, we hypothesize that body perception may be different in older, as compared to young adults. Here, we investigate this hypothesis by comparing the multisensory processing underlying BO and mBR in healthy older (> 65 years) and young individuals. First, we applied rigorous computational and psychophysical methods to assess alterations in mBR and BO quantitatively. We then modeled the manifold relationship between the observed body misperceptions and the potential underlying sensory, motor, and cognitive factors. The results highlight significant differences between the two groups, with higher distortions in perceived arm dimensions and an increased tendency to experience BO towards a virtual hand in the aged group. These differences in both mBR and BO are explained by the reduced proprioceptive abilities of older adults, suggesting a crucial role of proprioception in driving age-dependent plasticity in body representations. Overall, our modeling and experimental approach provide new perspectives on altered body perception during aging, suggesting that they stem from the physiological proprioceptive decline occurring in older adults, and laying the groundwork to generate prevention and stimulation strategies to restore accurate body perception in aging.

neuroscience↗

bioRxiv2021

Acute stress affects peripersonal space representation

Peripersonal space (PPS) is the region of space surrounding the body. It has a dedicated multisensory-motor representation, whose purpose is to predict and plan interactions with the environment, and which can vary depending on environmental circumstances. Here, we investigated the effect on the PPS representation of an experimentally induced stress response. We assessed PPS representation in healthy humans, before and after a stressful manipulation, by quantifying visuotactile interactions as a function of the distance from the body, while monitoring salivary cortisol concentration. Participants, who showed a cortisol stress response, presented enhanced visuotactile integration for stimuli close to the body and reduced for far stimuli. Conversely, individuals, with a less pronounced cortisol response, showed a reduced difference in visuotactile integration between the near and the far space. In our interpretation, physiological stress resulted in a freezing-like response, where multisensory-motor resources are allocated only to the area immediately surrounding the body.

neuroscience↗

bioRxiv2019

Rapid Recalibration of Peri-Personal Space; Psychophysical, Electrophysiological, and Neural Network Modeling Evidence

Interactions between individuals and the environment are mediated by the body and occur within the peri-personal space (PPS) - the space surrounding the body. The multisensory encoding of this space plastically adapts to different bodily constraints and stimuli features. However, these remapping effects have only been demonstrated on the time-scale of days, hours, or minutes. Yet, if PPS mediates human-environment interactions in an adaptive manner, its representation should be altered by sensory history on trial-to-trial timescale. Here we test this idea first via a visuo-tactile reaction time paradigm in augmented reality where participants are asked to respond as fast as possible to touch, as visual object approach them. Results demonstrate that reaction times to touch are facilitated as a function of visual proximity, and the sigmoidal function describing this facilitation shifts closer to the body if the immediately precedent trial had indexed a smaller visuo-tactile disparity (i.e., positive serial dependency). Next, we derive the electroencephalographic correlates of PPS and demonstrate that this measure is equally shaped by recent sensory history. Finally, we demonstrate that a validated neural network model of PPS is able to account for the present results via a simple Hebbian plasticity rule. The present findings suggest that PPS encoding remaps on a very rapid time-scale and is sensitive to recent sensory history.

neuroscience↗

bioRxiv2019

Multiple activities of the MatP protein are involved in post-replicative pairing of sister chromosomes in Escherichia coli

The ter region of the bacterial chromosome, where replication terminates, is the last to be segregated before cell division in Escherichia coli. Delayed segregation is controlled by the MatP protein, which binds to specific sites (matS) within ter, and interacts with other proteins such as ZapB. Here, we investigate the role of MatP by combining short-time mobility analyses of the ter locus with biochemical approaches. We find that ter mobility is similar to that of a non-ter locus, except when sister ter loci are paired after replication. This effect depends on MatP, the persistence of catenanes, and ZapB. We characterise MatP/DNA complexes and conclude that MatP binds DNA as a tetramer, but bridging matS sites in a DNA-rich environment remains infrequent. We propose that tetramerisation of MatP links matS sites with ZapB and/or with non-specific DNA to promote optimal pairing of sister ter regions until cell division.Competing Interest StatementThe authors have declared no competing interest.View Full Text

microbiology↗