Biology subjects

Avanzini, P.

Publications and source records attributed to Avanzini, P..

11 recordsLinked to original sources

bioRxiv2026

Simultaneous recordings link intracranial and scalp correlates of somatosensory awareness in humans

The electrophysiological events underlying the conscious perception of touch in humans remain elusive. Scalp-EEG studies have identified a negative deflection peaking 120-200 ms after stimulus onset, known as the N140. This component, recently reinterpreted as the somatosensory awareness negativity (N140/SAN), has been proposed as a putative marker of tactile awareness, but its underlying neuronal dynamics are still unknown. Intracranial studies have shown that responses to median nerve stimulation include, after an initial phasic activation mainly localized to primary somatosensory cortices, a predominantly insulo-opercular tonic broadband high-frequency activity (BHA; 50-150 Hz) that has been linked to tactile awareness. Yet these scalp and intracranial signatures have never been directly linked. Using simultaneous high-density scalp EEG and intracranial EEG recordings, we show that the N140/SAN is the scalp manifestation of the insulo-opercular local field potential that follows the BHA response to stimulation. By bridging invasive and non-invasive recordings our results identify the neural origins of the N140/SAN and connect scalp and intracranial correlates of somatosensory awareness.

neuroscience↗

bioRxiv2026

Behavioral Relevance Coding in Human Area 46 Precedes Selective Motor Activation to Action Targets

The lateral prefrontal cortex (LPFC) actively contributes to the adaptive control of goal-directed behavior. Evidence suggests that the LPFC encodes the behavioral relevance of stimuli, distinguishing action targets from irrelevant objects; however, how this selectivity emerges over time and integrates within large-scale cortical dynamics underlying action preparation remains unclear. We recorded stereo-electroencephalography (sEEG) activity from 43 patients affected by drug-resistant epilepsy while they prepared to grasp an object and compared it with passive observation of the same object. Gamma-band responses were used to characterize cortical responsiveness and to track the spatiotemporal propagation of activity during action preparation. Neural activity first emerged in the occipitotemporal cortex in both experimental conditions and then progressed along two parallel pathways: an intraparietal and a prefrontal one. The intraparietal pathway showed highly similar dynamics during both action preparation and passive observation, suggesting largely intention-independent visuospatial processing. In contrast, the prefrontal pathway exhibited progressively stronger selectivity for behaviorally relevant objects as activity advanced rostrally. Within this pathway, area 46 exhibited sustained responses selectively associated with action-relevant objects, preceding the similarly selective engagement of premotor and motor regions. Overall, our findings identify area 46 as a key node in whole-brain dynamics that orchestrates action preparation by integrating object relevance into executive control signals guiding premotor and motor engagement. NEW & NOTEWORTHYFilling a critical gap in system-level accounts of LPFC function, whole-brain recordings reveal that area 46 selectively codes object-related information relevant for action and gates motor region activity only when the object represents a true action target.

neuroscience↗

bioRxiv2026

A Virtual Reality Dataset to Support Hand Action Observation in Rehabilitation and Motor Learning Studies

The recovery of motor function is increasingly understood as a process influenced not only by physical training but also by perceptual and cognitive strategies. Action Observation Treatment (AOT), a neurorehabilitation approach in which patients observe goal-directed motor actions before executing them, has demonstrated clinical benefits; however, its wider implementation is hindered by a lack of standardized procedures. We present an open-access dataset of 33 upper limb gestures specifically developed to support the administration of Virtual Reality-based AOT (VR-AOT). The gestures were selected in collaboration with expert physiotherapists to ensure clinical relevance, and are provided as motion capture recordings along with Unity-based 3D animations embedded in configurable virtual scenes. The dataset is designed for flexibility, allowing users to modify parameters such as viewpoint, laterality, and repetition count. Technical validation confirms its usability and therapeutic applicability across multiple clinical and research contexts. This dataset offers a standardized yet customizable resource for developing and comparing VR-AOT protocols, with potential applications in neurorehabilitation and motor learning research.

neuroscience↗

bioRxiv2023

Architectural experience influences the processing of others' body expressions

The interplay between space and cognition is a crucial issue in Neuroscience leading to the development of multiple research fields. However, the relationship between architectural space, the movement of the inhabitants and their interactions has been too often neglected, failing to provide a unifying view of architectures capacity to modulate social cognition broadly. We bridge this gap by requesting participants to judge avatars emotional expression (high vs. low arousal) at the end of their promenade inside high- or low-arousing architectures. Stimuli were presented in virtual reality to ensure a dynamic, naturalistic experience. High-density EEG was recorded to assess the neural responses to the avatars presentation. Observing highly aroused avatars increased Late Positive Potentials (LPP), in line with previous evidence. Strikingly, 250 ms before the occurrence of the LPP, P200 amplitude increased due to the experience of low-arousing architectures paralleling increased subjective arousal reports and fixation times on the avatars head. Source localization highlighted a contribution of the right dorsal premotor cortex to both P200 and LPP. In conclusion, the immersive and dynamic architectural experience modulates human social cognition. In addition, the motor system plays a role in processing architecture and body expressions proving how the space and social cognition interplay is rooted in common neural substrates. This study demonstrates that the manipulation of mere architectural space is sufficient to influence human behavior in social interactions. Significance StatementIn the last thirty years the motor system has been recognized as a fundamental neural machinery for spatial and social cognition, making worthwhile the investigation of the interplay between architecture and social behavior. Here, we show that the motor system participates in the others body expression processing in two stages: the earliest influenced by the dynamic architectural experience, the latter modulated by the actual physical characteristics. These findings highlight the existence of motor neural substrates common to spatial and social cognition, with the architectural space exerting an early and possibly adapting effect on the later social experience. Since mere architectural forms influence human behavior, a proper spatial design could thus facilitate everyday social interactions.

neuroscience↗

bioRxiv2021

Simultaneous stereo-EEG and high-density scalp EEG recordings to study the effects of intracerebral stimulation parameters

BackgroundCortico-cortical evoked potentials (CCEPs) recorded by stereo-electroencephalography (SEEG) are a valuable clinical tool to investigate brain reactivity and effective connectivity. However, these invasive recordings are spatially sparse since they depend on clinical needs. This sparsity hampers systematic comparisons across-subjects, the detection of the whole-brain spatiotemporal properties of CCEPs, as well as their relationships with classic sensory evoked potentials. ObjectiveTo demonstrate that CCEPs recorded by high-density electroencephalography (hd-EEG) are sensitive to changes in stimulation parameters and compensate for the limitations typical of invasive recordings. MethodsSEEG and hd-EEG activities were simultaneously recorded during SPES in drug-resistant epileptic patients (N=36). Changes in stimulation parameters encompassed physical (pulse intensity and width), geometrical (angle and position with respect to white/grey matter) and topological (stimulated cortical area) properties. Differences were assessed by measuring the overall responses and the amplitude of N1 and N2 components of the CCEPs, and by their spectral profiles. ResultsWhile invasive and non-invasive CCEPs were generally correlated, differences in pulse duration, angle and stimulated cortical area were better captured by hd-EEG. Further, hd-EEG responses to SPES reproduced basic features of responses to transcranial magnetic stimulation and showed a much larger amplitude as compared to typical sensory evoked potentials. ConclusionsThe present results show that macroscale hd-EEG recordings are exquisitely sensitive to variations in SPES parameters, including local changes in physical and geometrical stimulus properties, while providing valuable information about whole-brain dynamics. Moreover, the common reference space across subjects represented by hd-EEG may facilitate the construction of a perturbational atlas of effective connectivity. HighlightsO_LICCEPs recorded with hd-EEG and SEEG are correlated. C_LIO_LIhd-EEG recording is highly sensitive to changes in stimulation parameters. C_LIO_LIhd-EEG responses show higher amplitude responses with respect to non-invasive ones. C_LIO_LISimultaneous recordings provide a fixed observation point across subjects. C_LI

neuroscience↗

bioRxiv2021

The value of corticospinal excitability and intracortical inhibition in predicting motor skill improvement driven by action observation

BACKGROUND AND OBJECTIVEAction observation can sustain motor skill improvement. At the neurophysiological level, action observation affects the excitability of the motor cortices, as measured by transcranial magnetic stimulation. However, whether the cortical modulations induced by action observation may explain the amount of motor improvement driven by action observation training (AOT) remains to be addressed. METHODSWe conducted a two-phase study involving 40 volunteers. First, we assessed the effect of action observation on corticospinal excitability (amplitude of motor evoked potentials), short-interval intracortical inhibition, and transcallosal inhibition (ipsilateral silent period). Subsequently, a randomized-controlled design was applied, with AOT participants asked to observe and then execute, as quickly as possible, a right-hand dexterity task six consecutive times, whereas controls had to observe a no-action video before performing the same task. RESULTSAOT participants showed greater performance improvement relative to controls. The amount of improvement in the AOT group was predicted by the amplitude of corticospinal modulation during action observation and even more by the amount of intracortical inhibition induced by action observation. Importantly, these relations were found specifically for the AOT group and not for the controls. CONCLUSIONSIn this study, we identified the neurophysiological signatures associated with, and potentially sustaining, the outcome of AOT. Intracortical inhibition driven by action observation plays a major role. These findings elucidate the cortical mechanisms underlying AOT efficacy and open to predictive assessments for the identification of potential responders to AOT, informing the rehabilitative treatment individualization.

neuroscience↗

bioRxiv2021

Hybrid EEG-EMG system to detect steering actions in car driving settings

Understanding mental processes in complex human behaviour is a key issue in the context of driving, representing a milestone for developing user-centred assistive driving devices. Here we propose a hybrid method based on electroencephalographic (EEG) and electromyographic (EMG) signatures to distinguish left from right steering in driving scenarios. Twenty-four participants took part in the experiment consisting of recordings 128-channel EEG as well as EMG activity from deltoids and forearm extensors in non-ecological and ecological steering tasks. Specifically, we identified the EEG mu rhythm modulation correlates with motor preparation of self-paced steering actions in the non-ecological task, while the concurrent EMG activity of the left (right) deltoids correlates with right (left) steering. Consequently, we exploited the mu rhythm de-synchronization resulting from the non-ecological task to detect the steering side by means of a cross-correlation analysis with the ecological EMG signals. Results returned significant cross-correlation values showing the coupling between the non-ecological EEG feature and the muscular activity collected in ecological driving conditions. Moreover, such cross-correlation patterns discriminate left from right steering with an earlier dynamic with respect to the single EMG signal. This hybrid system overcomes the limitation of the EEG signals collected in ecological settings such as low reliability, accuracy and adaptability, thus adding to the EMG the characteristic predictive power of the cerebral data. These results are a proof of concept of how it is possible to complement different physiological signals to control the level of assistance needed by the driver.

neuroscience↗

bioRxiv2021

An in-vivo validation of ESI methods with focal sources

Electrical source imaging (ESI) aims at reconstructing the electrical brain activity from measurements of the electric field on the scalp. Even though the localization of single focal sources should be relatively straightforward, different methods provide diverse solutions due to the different underlying assumptions. Furthermore, their input parameter(s) further affects the solution provided by each method, making localization even more challenging. In addition, validations and comparisons are typically performed either on synthetic data or through post-operative outcomes, in both cases with considerable limitations. We use an in-vivo high-density EEG dataset recorded during intracranial single pulse electrical stimulation, in which the true sources are substantially dipolar and their locations are known. We compare ten different ESI methods under multiple choices of input parameters, to assess the accuracy of the best reconstruction, as well as the impact of the parameters on the localization performance. Best reconstructions often fall within 1 cm from the true source, with more accurate methods outperforming less accurate ones by 1 cm, on average. Expectedly, dipolar methods tend to outperform distributed methods. Sensitivity to input parameters varies widely between methods. Depth weighting played no role for three out of six methods implementing it. In terms of regularization parameters, for several distributed methods SNR=1 unexpectedly turned out to be the best choice among the tested ones. Our data show similar levels of accuracy of ESI techniques when applied to "conventional" (32 channels) and dense (64, 128, 256 channels) EEG recordings. Overall findings reinforce the importance that ESI may have in the clinical context, especially when applied to identify the surgical target in potential candidates for epilepsy surgery.

neuroscience↗

bioRxiv2021

A comparative study between state-of-the-art MRI deidentification and AnonyMI, a new method combining re-identification risk reduction and geometrical preservation

Deidentifying MRIs constitutes an imperative challenge, as it aims at precluding the possibility of re-identification of a research subject or patient, but at the same time it should preserve as much geometrical information as possible, in order to maximize data reusability and to facilitate interoperability. Although several deidentification methods exist, no comprehensive and comparative evaluation of deidentification performance has been carried out across them. Moreover, the possible ways these methods can compromise subsequent analysis has not been exhaustively tested. To tackle these issues, we developed AnonyMI, a novel MRI deidentification method, implemented as a user-friendly 3D Slicer plugin-in, which aims at providing a balance between identity protection and geometrical preservation. To test these features, we performed two series of analyses on which we compared AnonyMI to other two state-of-the-art methods, to evaluate, at the same time, how efficient they are at deidentifying MRIs and how much they affect subsequent analyses, with particular emphasis on source localization procedures. Our results show that all three methods significantly reduce the re-identification risk but AnonyMI provides the best geometrical conservation. Notably, it also offers several technical advantages such as a user-friendly interface, multiple input-output capabilities, the possibility of being tailored to specific needs, batch processing and efficient visualization for quality assurance.

neuroscience↗

bioRxiv2020

Simultaneous human intracerebral stimulation and HD-EEG: ground-truth for source localization methods

Precisely localizing the sources of brain activity as recorded by EEG is a fundamental procedure and a major challenge for both research and clinical practice. Even though many methods and algorithms have been proposed, their relative advantages and limitations are still not well established. Moreover, these methods involve tuning multiple parameters, for which no principled way of selection exists yet. These uncertainties are emphasized due to the lack of ground-truth for their validation and testing. Here we provide the first open dataset that comprises EEG recorded electrical activity originating from precisely known locations inside the brain of living humans. High-density EEG was recorded as single-pulse biphasic currents were delivered at intensities ranging from 0.1 to 5 mA through stereotactically implanted electrodes in diverse brain regions during pre-surgical evaluation of patients with drug-resistant epilepsy. The uses of this dataset range from the estimation of in vivo tissue conductivity to the development, validation and testing of forward and inverse solution methods.

neuroscience↗

bioRxiv2020

Stereo-EEG reveals rich cortical dynamics in humans coping with difficult action discrimination.

Visual perception of others actions is important for social interactions, and the ability to do so, even when one gets only brief glimpses of others behavior, may be crucial for survival. At present it is unknown how the human brain solves this problem. Imaging studies have promoted the idea that the multiple demand (MD) system, a domain general system of the human brain, operates in difficult cognitive and perceptual tasks, but not in tasks in which sensory information is reduced. Functional imaging, based on slow hemodynamic responses, may miss or standardize neural events with very diverse time courses. Here we exploited the temporal resolution of stereo-EEG to study directly cortical activity when human subjects must judge the actions of others, but only get brief glimpses of others activity, because the videos were truncated. Multiple cortical regions increased their activity in the difficult action discrimination, relative to the easy task when the complete video was visible. The majority of these regions belonged to the MD system, being located in parietal or prefrontal cortex. The variety of time courses, lasting from a few 100ms to several seconds, allowed us to disentangle control from effector regions, the latter processing observed actions. This distinction was further supported by relationships with behavior. A key operation within the control clusters was the prediction of erroneous responses, which was initiated in the PPC soon after the end of the truncated video. The time courses further suggested that MD regions not only exert control, but also perform various evaluations of the effort, important for efficient and intelligent behavior. We observed also increases outside the MD system, in temporo-parietal cortex, which may provide contextual information about variables related to the observed action, such as the actor, the object or the scene. Furthermore, to cope with the brief sensory input, the MD system called upon warning regions reacting to the static picture of the actor presented just before the video. We conclude that discrimination of brief observed actions indeed involves the MD system, which is thus is more general than assumed so far. WE also show that the MD system is more complex than assumed, as it includes evaluation of control, and more flexible, as it interacts with other systems than simply the effector circuit of the task.

neuroscience↗