Biology subjects

Bottari, D.

Publications and source records attributed to Bottari, D..

17 recordsLinked to original sources

bioRxiv2026

Newborns modulate and synchronise their Non-Nutritive Sucking behaviour to the temporal structure of sound

Sensorimotor synchronization, the ability to align motor behaviour with the temporal structure of external stimuli, is thought to emerge gradually during development, but its origins remain unclear. Here, we investigated whether newborns can adapt their sucking behaviour and synchronise it to the temporal structure of auditory stimuli within the first days of life. Forty-one healthy full-term newborns (24-72 hours old) were exposed to two three-minute auditory streams differing in temporal structure: a highly structured stream with a stable temporal pattern and a highly variant stream with greater temporal variability, while their non-nutritive sucking (NNS) was continuously recorded. We assessed changes in NNS frequency and pressure and quantified NNS-sound coupling using magnitude-squared coherence at frequencies distinctive to each auditory stream. Structured stimulation promoted a more organised NNS, with more suck bursts than the variant stream, and increased sucking vigour, with a transiently higher suck peak rate during the first minute relative to the variant stream and greater suck pressure relative to silence. Coherence analyses revealed that coherence was selectively higher at the frequencies distinctive to each auditory stream, both for the structured and the highly variant stimulus. These findings show that, within hours of birth, NNS behaviour can selectively align with stimulus-specific temporal regularities, even when these are weakly predictable and lack a dominant periodicity. This early capacity to extract temporal structure and coordinate motor behaviour may provide a foundation for the subsequent development of sensorimotor synchronisation.

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bioRxiv2026

Lack of vision shifts occipital dynamics toward a frontal-like regime and enhances top-down connectivity

The human occipital cortex is robustly repurposed for non-visual cognition after blindness, yet it remains unknown whether this functional reassignment is accompanied by a fundamental retuning of its intrinsic neural dynamics. Here, we recorded the electroencephalographic (EEG) responses to transcranial magnetic stimulation (TMS) of frontal and occipital areas to causally probe local cortical reactivity and large-scale effective connectivity in 16 blind individuals and 16 sighted controls. Direct perturbation of the occipital cortex revealed a profound shift in its intrinsic operating regime: compared with sighted participants, blind individuals exhibited faster, lower-amplitude TMS-evoked potentials that closely resembled the electrophysiological signature of the frontal cortex, which turned out to be comparable in the two populations. At the network level, source analyses further showed a specific enhancement of frontal-to-occipital effective connectivity, whereas occipital-to-frontal propagation remained unchanged. Importantly, among blind participants, faster occipital dynamics were associated with stronger frontal-driven occipital recruitment, directly linking local temporal retuning to enhanced top-down network influence. Together, these findings indicate that blindness reshapes both the intrinsic dynamics and large-scale integration of the occipital cortex. We propose that successful functional reassignment of the occipital cortex requires not only changes in cortical connectivity but also a tuning of the temporal operating regime toward a faster dynamics, enabling its embedding into distributed cognitive networks and providing a mechanistic framework for the functional reassignment of deafferented cortex.

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bioRxiv2026

Visual speech supports phonetic attunement in the absence of early auditory input

The first year of life is considered a sensitive period for the acquisition of phonetic categories, a hallmark of successful native language specialization. The extent to which this process depends on early auditory experience and intrinsic biological constraints remains unresolved. We measured neural encoding of continuous natural speech in hearing children (HC) and cochlear implant (CI) users with congenital or acquired deafness, contrasting children with and without access to auditory input in the first year of life. Speech encoding was present across all groups, but its specificity depended on early input: auditory phonetic features were encoded only in children exposed to speech within the first year, whereas visually discriminable phonetic features were encoded regardless of auditory deprivation. These findings show that early sensory input gates phonetic attunement; this constraint is not limited to or grounded in audition but instead reveals a sensitive period that is modality-flexible in mechanism and experience-dependent in expression.

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bioRxiv2026

Chronic acoustic degradation via cochlear implants alters predictive processing of audiovisual speech

This study provides the first neurophysiological evidence of how cochlear implant (CI) input affects predictive processing during audiovisual language comprehension in deaf individuals. Using EEG, we compared 18 CI users with 18 normal-hearing (NH) controls during sentence comprehension where final word predictability was determined by high or low semantic constraint (HC vs. LC) of the preceding sentence frame. Between sentence frame and final word, a 800 ms silent gap was introduced. Mouth visibility was manipulated during sentence frames (visible or digitally occluded; V+ vs. V-), while the final words were always presented with the mouth visible. In NH participants, lower-beta power (12-15 Hz) in left frontal and central sensors decreased for HC vs. LC contexts during the pre-target silent gap, but only when the mouths was visible, suggesting active prediction generation. In CI users, this lower beta power decrease was absent. After final word presentation, both groups showed N400 predictability effects, indicating preserved prediction evaluation. However, CI users exhibited extended N400 effects in the V+ condition, suggesting additional processing demands. Across all participants, pre-target beta modulations correlated with language production abilities, supporting prediction-by-production frameworks. Within CI users, poorer audiometric thresholds correlated with larger N400 constraint effects, possibly indicating greater reliance on contextual prediction to compensate for degraded sensory input. These findings demonstrate that CI-mediated perception alters the neural mechanisms of prediction generation. The link between production skills and predictive mechanisms suggests that strengthening expressive language abilities may enhance predictive processing in CI users.

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bioRxiv2025

Ocular speech tracking persists in blindness, but its dynamics and oculo-cerebral connectivity depend on visual status

While eye movements have been shown to track the speech envelope, it is unknown whether this reflects a hard-wired mechanism or one shaped by (lifetime) audiovisual experience. Further, questions remain about whether ocular tracking is modulated by speech intelligibility and which brain regions drive these synchronized eye movements. Here, we investigate ocular speech tracking in blindfolded early blind, late blind, and sighted individuals using magnetoencephalography (MEG) and source-reconstructed oculomotor signals while participants listened to narrative speech of varying intelligibility. We found that oculomotor activity tracks acoustic speech features and, unlike neural speech tracking, is not modulated by intelligibility. Interestingly, we found effects reflected in two frequency-specific components: a low-frequency ([~]1 Hz) effect present across all groups, indicating that visual experience is not required, and a high-frequency ([~]6 Hz) effect reduced in early- and late-blind individuals. Moreover, this finding is not driven by cerebro-ocular connectivity, as late-blind individuals exhibit stronger connectivity between the eyes and the left temporal cortices without a corresponding increase in ocular tracking. In conclusion, ocular speech tracking seems to respond selectively to acoustic but not to intelligibility features of speech, and it does not require visual experience to develop. It may thus represent a hard-wired oculomotor mechanism within the oculo-cerebral network involved in speech processing. Significance StatementEye movements provide a unique window into the interaction between auditory and visual systems. By studying early blind, late blind, and sighted individuals, we demonstrate that speech-related eye movements arise from at least two distinct mechanisms: a low-frequency component that occurs independently of (lifetime) visual experience and is linked to processing of acoustic speech features, and a high-frequency component shaped by prior visual exposure. Importantly, speech intelligibility - unlike its impact on neural measures - does not modulate these ocular responses. This dissociation suggests that eye movements reflect mechanisms of spoken language processing that are independent of intelligibility, thereby revealing novel pathways of auditory-motor coupling and broadening our understanding of sensory integration in the absence of vision.

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bioRxiv2024

Resilience and vulnerability of speech neural tracking to early auditory deprivation

Infants are born with biological biases that favour language acquisition. One is the auditory systems ability to track the envelope of continuous speech, a pivotal feature for spoken language comprehension in adulthood. However, the extent to which neural speech tracking relies on postnatal auditory experience remains unknown. In this case-control study, we tested children with or without access to functional hearing in the first year of life after they received cochlear implants (CIs) for hearing restoration. We measured neural speech tracking in CI users with a congenital bilateral profound deafness (CD) or who acquired it later in development (AD; minimum auditory experience after birth 12 months), as well as in two groups of hearing controls listening to original (HC) or vocoded-speech (HC-v). Remarkably, neural speech tracking in children with CIs was unaffected by the absence of perinatal auditory experience. Regardless of deafness onset, CI users and HC exhibited a similar neural tracking magnitude at short timescales [~]50- 130 ms (P1TRF) of brain activity. However, this neural tracking phase (P1TRF) was delayed in CI users, and its timing depended on the age of hearing restoration. Conversely, at longer timescales [~]130-260 ms (N2TRF) of brain activity, speech tracking was substantially dampened in participants with CIs, thereby accounting for their comprehension deficits. Speech tracking in HC listening to vocoded-speech and in a phantom head-model with CIs suggested that neural processing differences between HC and CI children could not merely be explained by the degraded acoustic stimulation, nor by electrical artifacts of the implants. These findings highlight (i) the resilience of sensory components of neural speech tracking to the lack of hearing in the first year of life, (ii) the crucial role played when hearing restoration takes place in mitigating the impact of atypical auditory experience, (iii) the vulnerability of higher hierarchical levels of speech processing in CI users.

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bioRxiv2024

The impact of face masks on face-to-face neural tracking of speech: auditory and visual obstacles

Face masks provide fundamental protection against the transmission of respiratory viruses but hamper communication. We estimated auditory and visual obstacles generated by face masks on communication by measuring the neural tracking of face-to-face speech. To this end, we recorded the EEG while participants were exposed to naturalistic audio-visual speech, embedded in multi-talker noise, in three contexts: (i) no-mask (audio-visual information was fully available), (ii) virtual mask (occluded lips, but intact audio), and (iii) real mask (occluded lips and degraded audio). The neural tracking of lip movements and the sound envelope of speech was measured through backward modeling, that is, by reconstructing stimulus properties from neural activity. Behaviorally, face masks increased listening -phonological-errors in speech content retrieval and perceived listening difficulty. At the neural level, we observed that the occlusion of the mouth abolished lip tracking and dampened neural tracking of the speech envelope at the earliest processing stages. Degraded acoustic information due to face mask filtering altered neural tracking at later processing stages instead. Finally, a consistent link emerged between the increment of listening perceived difficulty and the drop in reconstruction performance of speech envelope when attending to a speaker wearing a face mask. Results clearly dissociated the visual and auditory impacts of face masks on face-to-face neural tracking of speech. While face masks hampered the ability to predict and integrate audio-visual speech, the auditory filter generated by face masks impacted the neural processing stages typically associated with auditory selective attention. The link between perceived difficulty and neural tracking drop provided evidence of a major impact of face masks on the metacognitive levels subtending speech processing.

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bioRxiv2023

Brain encoding of naturalistic, continuous, and unpredictable tactile events

AbstractStudies employing EEG to measure somatosensory responses have been typically optimized to compute event-related potentials in response to discrete events (ERPs). However, tactile interactions involve continuous processing of non-stationary inputs that change in location, duration, and intensity. To fill this gap, this study aims to demonstrate the possibility of measuring the neural tracking of continuous and unpredictable tactile information. Twenty-seven young adults (females = 15) were continuously and passively stimulated with a random series of gentle brushes on single fingers of each hand, which were covered from view. Thus, tactile stimulations were unique for each participant, and stimulated fingers. An encoding model measured the degree of synchronization between brain activity and continuous tactile input, generating a temporal response function (TRF). Brain topographies associated with the encoding of each finger stimulation showed a contralateral response at central sensors starting at 50 ms and peaking at about 140 ms of lag, followed by a bilateral response at about 240 ms. A series of analyses highlighted that reliable tactile TRF emerged after just 3 minutes of stimulation. Strikingly, topographical patterns of the TRF allowed discriminating digit lateralization across hands and digit representation within each hand. Our results demonstrated for the first time the possibility of using EEG to measure the neural tracking of a naturalistic, continuous, and unpredictable stimulation in the somatosensory domain. Crucially, this approach allows the study of brain activity following individualized, idiosyncratic tactile events to the fingers. Significant StatementThis study expands the current research conducted on neural tracking, opening the exploration of idiosyncratic tactile events and overcoming constraints of laboratory tasks that typically rely on discrete events. We validated a protocol for the ecological investigations of continuous, slow, tactile processing of the hands. The employed approach enriches the possible use of the EEG to characterize somatosensory neural representations of tactile events. Findings unravel coherent neural responses to continuous and naturalistic touch, with sensitivity for digit lateralization and representation.

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bioRxiv2023

Abstract, modality-specific and experience-dependent coding of affect in the human brain

Emotion and perception are tightly intertwined, as affective experiences often arise from the appraisal of sensory information. Nonetheless, whether the brain encodes emotional instances using a sensory-specific code or in a more abstract manner is unclear. Here, we answer this question by measuring the association between emotion ratings collected during a unisensory or multisensory presentation of a full-length movie and brain activity recorded in typically-developed, congenitally blind and congenitally deaf participants. Emotional instances are encoded in a vast network encompassing sensory, prefrontal, and temporal cortices. Within this network, the ventromedial prefrontal cortex stores a categorical representation of emotion independent of modality and experience, and the posterior superior temporal cortex maps valence using an abstract code. Sensory experience more than modality impacts how the brain organizes emotional information outside supramodal regions, suggesting the existence of a scaffold for the representation of emotional states where sensory inputs during development shape its functioning.

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bioRxiv2023

Hemispheric asymmetries in auditory cortex reflect discriminative responses to temporal details or summary statistics of stationary sounds.

The processing of stationary sounds relies on both local features and compact representations. As local information is compressed into summary statistics, abstract representations emerge. Whether the brain is endowed with distinct neural architectures overseeing such computations is unknown. In this magnetoencephalography (MEG) study, we employed a validated protocol to localize cortical correlates of local and summary representations, exposing participants to triplets of synthetic sound textures systematically varying for either local details or summary statistics. Sounds also varied for their sound duration, specifically short (40ms) or long (478ms). Results revealed clear distinct activation patterns for local features and summary statistics changes. Such activations diverged in magnitude, spatiotemporal distribution, and hemispheric lateralization. For short sounds, a change in local features, compared to summary statistics, predominantly activated the right hemisphere. Conversely, for long sounds, a change in summary statistics elicited higher activation than a change in local features in both hemispheres. Specifically, while the right auditory cortex was responding more to changes in local features or summary statistics depending on sound duration (short or long, respectively), the left frontal lobe was selectively engaged in processing a change in summary statistics at a long sound duration. These findings provide insights into the neural mechanisms underlying the computation of local and summary acoustic information and highlight the involvement of distinct cortical pathways and hemispheric lateralization in auditory processing at different temporal resolutions. Significant StatementWe revealed hemispheric specializations for auditory computations at high (local) and low (summary statistics) temporal resolutions. The right hemisphere was engaged for both computations, while the left hemisphere responded more to summary statistics changes. These findings highlight the multifaceted functions of the right hemisphere in capturing acoustic properties of stationary sounds and the left hemispheres involvement in processing abstract representations.

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bioRxiv2022

Early visual cortex tracks speech envelope in the absence of visual input

Neural entrainment to continuous speech is typically observed within the language network and can be modulated by both low-level acoustic features and high-level meaningful linguistic units (e.g., phonemes, phrases, and sentences). Recent evidence showed that visual cortex may entrain to speech envelope, however its putative role in the hierarchy of speech processing remains unknown. We tested blindfolded participants who listened to semantically meaningful or meaningless stories, either in quiet or embedded in multi-talker babble noise. Entrainment to speech was assessed with forward linear modeling of participants EEG activity. We investigated (1) low-level acoustic effects by contrasting neural tracking of speech presented in quiet or noise and (2) high-level linguistic effects by contrasting neural tracking to meaningful or meaningless stories. Results showed that envelope tracking was enhanced and delayed for speech embedded in noise compared to quiet. When semantic information was missing, entrainment to speech envelope was fastened and reduced. Source modeling revealed that envelope tracking engaged wide neural networks beyond the auditory cortex, including early visual cortex. Surprisingly, while no clear influence of semantic content was found, the magnitude of visual cortex entrainment was affected by low-level features. The decrease of sound SNR-level dampened visual cortex tracking, suggesting an active suppressing mechanism in challenging listening conditions. Altogether, these findings provide further evidence of a functional role of early visual cortex in the entrainment to continuous speech.

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bioRxiv2022

Short-term monocular deprivation boosts neural responsiveness to audio-visual events for the undeprived eye

A brief period of monocular deprivation (MD) induces short-term plasticity of the adult visual system. Whether MD elicits changes beyond visual processing is yet unclear. Here, we assessed the specific impact of MD on multisensory processes. Neural oscillations associated with visual and audio-visual processing were measured for both the deprived and the undeprived eye. Results revealed that MD changed neural activities associated with unimodal and multisensory processes in an eye-specific manner. Selectively for the deprived eye, alpha activity was reduced within the first 150 ms of visual processing. Conversely, gamma activity was enhanced in response to audio-visual events only for the undeprived eye within 100-300 ms after stimulus onset. The analysis of gamma responses to unimodal auditory events revealed that MD elicited a crossmodal upweighting for the undeprived eye. Distributed source modeling suggested that the right parietal cortex played a major role in all neural effects induced by MD. Finally, visual and audio-visual processing alterations emerged selectively for the induced (but not the evoked) component of the neural oscillations, indicating a major role of feedback connectivity. These findings support a model in which MD increases excitability to visual events for the deprived eye and to audio-visual and auditory events for the undeprived eye. On the one hand, these results reveal the causal impact of MD on both unisensory and multisensory processes but with distinct frequency-specific profiles. On the other hand, they highlight the feedback nature of short-term neural plasticity. Overall this study shed light on the high flexibility and interdependence of unimodal and multisensory functions. Highlights- We unveiled the impact of temporary MD on visual and audio-visual processing - MD enhanced visual excitability for the deprived eye - MD boosted neural responses to audio-visual events for the undeprived eye - Analyses of auditory processing revealed crossmodal effects following MD - Short-term MD primarily affects induced, non-phase-locked, oscillatory activity

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bioRxiv2022

Distinct cortical responses to Auditory Statistics: pre-attentive discriminations based on local and global representations

The auditory system relies on both local and summary representations; acoustic local features exceeding system constraints are compacted into a set of summary statistics. Such compression is pivotal for sound-object recognition. Here, we assessed whether computations subtending local and statistical representations of sounds could be distinguished at the neural level. A computational auditory model was employed to extract auditory statistics from natural sound textures (i.e., fire, rain) and to generate synthetic exemplars where local and statistical properties were controlled. Twenty-four human participants were passively exposed to auditory streams while the EEG was recorded. Each stream could consist of short, medium, or long sounds to vary the amount of acoustic information. Short and long sounds were expected to engage local or summary statistics representations, respectively. Data revealed a clear dissociation. Compared to summary-based ones, auditory-evoked responses based on local information were selectively greater in magnitude in short sounds. Opposite patterns emerged for longer sounds. Neural oscillations revealed that local features and summary statistics rely on neural activity occurring at different temporal scales, faster (beta) or slower (theta-alpha). These dissociations emerged automatically without explicit engagement in a discrimination task. Overall, this study demonstrates that the auditory system developed distinct coding mechanisms to discriminate changes in the acoustic environment based on fine structure and summary representations. SIGNIFICANCE STATEMENTPrior to this study, it was unknown whether we could measure auditory discrimination based on local temporal features or spectrotemporal statistics properties of sounds from brain responses. Results show that the two auditory modes of sound discrimination (local and summary statistics) are automatically attuned to the temporal resolution (high or low) at which a change has occurred. In line with the temporal resolutions of auditory statistics, faster or slower neural oscillations (temporal scales) code sound changes based on local or summary representations. These findings expand our knowledge of some fundamental mechanisms underlying the function of the auditory system.

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bioRxiv2022

A modality independent proto-organization of human multisensory areas

The processing of multisensory information is based upon the capacity of brain regions, such as the superior temporal cortex, to combine information across modalities. However, it is still unclear whether the representation of coherent auditory and visual events does require any prior audiovisual experience to develop and function. In three fMRI experiments, intersubject correlation analysis measured brain synchronization during the presentation of an audiovisual, audio-only or video-only versions of the same narrative in distinct groups of sensory-deprived (congenitally blind and deaf) and typically-developed individuals. The superior temporal cortex synchronized across auditory and visual conditions, even in sensory-deprived individuals who lack any audiovisual experience. This synchronization was primarily mediated by low-level perceptual features and relied on a similar modality-independent topographical organization of temporal dynamics. The human superior temporal cortex is naturally endowed with a functional scaffolding to yield a common representation across multisensory events.

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bioRxiv2021

The Size-Weight Illusion is unimpaired in individuals with a history of congenital visual deprivation

Visual deprivation in childhood can lead to lifelong impairments in visual and multisensory processing. Here, the Size-Weight-Illusion was used to test whether visuo-haptic integration recovers after sight restoration. In Experiment 1, congenital (CC: 7 (3F), 8-35 years) and developmental cataract reversal individuals (DC: 9 (2F), 8-37 years), as well as congenitally blind (CB: 2 (1F), 33 and 44 years) and normally sighted individuals (SC: 10 (7F), 19-36 years) perceived larger objects as lighter than smaller objects of the same weight. In Experiment 2, CC (6 (1F), 17-44.7 years) and SC (7 (5F), 21-29 years) individuals performed identically when tested without haptic size cues. Together, this suggested that early visual experience is not necessary to perceive the Size-Weight-Illusion.

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bioRxiv2020

Auditory statistics development does not rely on vision, but the processing of sound local features is hampered by late-onset sight loss

The human auditory system relies on both detailed and summarized representations to recognize different sounds. As local features can exceed the storage capacity, average statistics are computed over time to generate more compact representations at the expense of temporal details availability. This study aimed to identify whether these fundamental sound analyses develop and function exclusively under the influence of the auditory system or interact with other modalities, such as vision. We employed a validated computational synthesis approach allowing to control directly statistical properties embedded in sounds. To address whether the two modes of auditory representation (local features processing and statistical averaging) are influenced by the availability of visual input in different phases of development, we tested samples of sighted controls (SC), congenitally blind (CB), and late-onset (> 10 years of age) blind (LB) individuals in two separate experiments which uncovered auditory statistics computations from behavioral performances. In experiment 1, performance relied on the availability of local features at specific time points; in experiment 2, performance benefited from computing average statistics over longer durations. As expected, when sound duration increased, detailed representation gave way to summary statistics in SC. In both experiments, the sample of CB individuals displayed a remarkably similar performance revealing that both local and global auditory processes are not altered by blindness since birth. Conversely, LB individuals performed poorly compared to the other groups when relying on local features, with no impact on statistical averaging. The dampening in the performance was not associated with the onset and duration of visual deprivation. Results provide clear evidence that vision is not necessary for the development of the auditory computations tested here. Remarkably, a functional interplay between acoustic details processing and vision emerges at later developmental phases. Findings are consistent with a model in which the efficiency of local auditory processing is vulnerable in case sight becomes unavailable. Ultimately results are in favor of a shared computational framework for auditory and visual processing of local features, which emerges in late development.

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bioRxiv2020

Auditory features modelling demonstrates sound envelope representation in striate cortex

The striate cortex is no longer considered exclusively visual in its function. Proofs that its activity is modulated by acoustic inputs have accrued. By employing category-based and feature modeling approaches, here we characterized V1 activity (in absence of retinal input) during the processing of natural and synthetically derived sounds. First, we showed that distinct sound categories could be dissociated by the analysis of V1 multivoxel response patterns. Hence, we assessed whether a hallmark of sound neural representations is mapped in V1. In each sound category, we modeled sound envelopes and assessed whether these were represented at the single-voxel level in the striate cortex and, as a control, in the temporal cortex. The hierarchical organization of sound categories allowed to exert control over dimensions that could spuriously lead to sound envelope V1 mapping. Variations of sound amplitude over time were successfully decoded in V1 regardless of the category class. Results confirm that the human striate cortex receives acoustic category-based input and demonstrate that V1 is a genuine locus of sound envelope representation.

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