Biology subjects

Barbero, F. M.

Publications and source records attributed to Barbero, F. M..

6 recordsLinked to original sources

bioRxiv2026

Neural categorisation of rhythm in human newborns

Music is ubiquitous across cultures, and humans engage in social interactions through music from early in life. A cornerstone of these interactions is rhythm categorisation, allowing the sheer diversity of rhythmic inputs to be mapped onto internal rhythm categories. The pervasiveness of certain rhythm categories across cultures suggests that rhythm categorisation may be partially rooted in neurobiological predispositions constraining the internal representations of rhythm. However, this view appears to conflict with the diversity of music practices across cultures, which points to a role of experience in rhythm categorisation. To assess the relative contributions of neurobiological predispositions and experience, we tested 0- to 3-day-old newborns, capitalising on their minimal postnatal experience with music. Using electroencephalography (EEG), we recorded, in newborns and adults, brain responses to drum sounds whose pattern of relative interval duration ranged from isochronous to long-short rhythms (1:1 - 2:1 interval ratio). Results indicate significant categorisation in newborns's neural responses, with a representational structure that correlate with those of adults, yet with a greater degree of differentiation across rhythms. These findings reveal neurobiological predispositions enabling rhythm categorisation to be present at birth and further shaped across the lifespan, highlighting the evolutionary roots and plasticity supporting this human cultural practice.

neuroscience↗

bioRxiv2025

Two senses, one rhythm: Pre- and post-stimulus neural states predict perceived audio-visual synchrony

How does the brain integrate or segregate multiple sensory inputs? In our study, we used magnetoencephalography to comprehensively investigate local and network dynamics before and after the presentation of sequences of beeps and flashes that are sometimes perceived as synchronous or asynchronous. Frequency-tagging and spectral analysis revealed that under identical physical conditions, subjective perceptual fusion of multisensory signals elicits stronger evoked sensory responses in both visual and auditory cortices. Crucially, perceptual fusion is preceded by locally reduced pre-stimulus alpha activity, as well as enhanced functional connectivity between auditory and visual cortices within the pre-stimulus gamma activity. We also show that pre-stimulus neuronal states in the occipital cortex predict post-stimulus sensory responses to auditory sequences in the temporal cortex, but not the opposite. The current findings provide evidence that the perceptual fusion of multisensory events relate to a complex interplay between local and inter-sensory neuronal states before and after stimulus presentation. Significance StatementHow does the brain blend information from multiple sensory systems into one holistic perception? We developed a novel frequency-tagging paradigm in Magnetoencephalography (MEG) to robustly estimate the sensory responses to a series of flashes and beeps in early sensory areas, and to demonstrate how these responses are shaped by ongoing fluctuations in local, and long-range network activity. By combining the steady-state method with spectral, and functional connectivity analysis of ongoing oscillations in source space, the current study provides novel insights into the relationship between internal brain states and the way we perceive multisensory events.

neuroscience↗

bioRxiv2024

Revealing rhythm categorization in human brain activity

Humans across cultures show an outstanding capacity to perceive, learn, and produce musical rhythms. These skills rely on mapping the infinite space of possible rhythmic sensory inputs onto a finite set of internal rhythm categories. What are the brain processes underlying rhythm categorization? We used electroencephalography (EEG) to measure brain activity as human participants listened to a continuum of rhythmic sequences characterized by repeating patterns of two inter-onset intervals. Using frequency and representational similarity analyses, we show that brain activity does not merely track the temporal structure of rhythmic inputs, but, instead, automatically produces categorical representation of rhythms. Surprisingly, despite this automaticity, these rhythm categories do not arise in the earliest stages of the ascending auditory pathway, but show strong similarity between implicit neural and overt behavioral responses. Together, these results and methodological advances constitute a critical step towards understanding the biological roots and diversity of musical behaviors across cultures.

neuroscience↗

bioRxiv2022

Automatic brain categorization of discrete auditory emotion expressions

Seamlessly extracting emotional information from voices is crucial for efficient interpersonal communication. However, it remains unclear how the brain categorizes vocal expressions of emotion beyond the processing of their acoustic features. In our study, we developed a new approach combining electroencephalographic recordings (EEG) in humans with an oddball frequency tagging paradigm to automatically tag neural responses to specific emotion expressions. Participants were presented with a periodic stream of heterogeneous non-verbal emotional vocalizations belonging to five emotion categories (Anger, Disgust, Fear, Happiness, Sadness) at 2.5 Hz. Importantly, unbeknown to the participant, a specific emotion category appeared at an oddball presentation rate at 0.83 Hz that would elicit an additional response in the EEG spectrum only if the brain discriminates the target emotion category from other emotion categories and generalizes across heterogeneous exemplars of the target emotion category. Stimuli were matched across emotion categories for harmonicity-to-noise ratio, spectral center of gravity, pitch, envelope, and early auditory peripheral processing via the simulated output of the cochlea. Additionally, participants were presented with a scrambled version of the stimuli with identical spectral content and periodicity but disrupted intelligibility. We observed that in addition to the responses at the general presentation frequency (2.5 Hz) in both intact and scrambled sequences, a peak in the EEG spectrum at the oddball emotion presentation rate (0.83 Hz) and its harmonics emerged in the intact sequence only. The absence of response at the oddball frequency in the scrambled sequence in conjunction to our stimuli matching procedure suggests that the categorical brain response elicited by a specific emotion is at least partially independent from low-level acoustic features of the sounds. Further, different topographies were observed when fearful or happy sounds were presented as an oddball that supports the idea of different representations of distinct discrete emotions in the brain. Our paradigm revealed the ability of the brain to automatically categorize non-verbal vocal emotion expressions objectively (behavior-free), rapidly (in few minutes of recording time) and robustly (high signal-to-noise ratio), making it a useful tool to study vocal emotion processing and auditory categorization in general in populations where brain recordings are more challenging.

neuroscience↗

bioRxiv2021

A robust voice-selective response in the human brain as revealed by electrophysiological recordings and fast periodic auditory stimulation

Voices are arguably among the most relevant sounds in humans everyday life, and several studies have suggested the existence of voice-selective regions in the human brain. Despite two decades of research, defining the human brain regions supporting voice recognition remains challenging. Moreover, whether neural selectivity to voices is merely driven by acoustic properties specific to human voices (e.g. spectrogram, harmonicity), or whether it also reflects a higher-level categorization response is still under debate. Here, we objectively measured rapid automatic categorization responses to human voices with Fast Periodic Auditory Stimulation (FPAS) combined with electroencephalography (EEG). Participants were tested with stimulation sequences containing heterogeneous non-vocal sounds from different categories presented at 4 Hz (i.e., 4 stimuli/second), with vocal sounds appearing every 3 stimuli (1.333 Hz). A few minutes of stimulation are sufficient to elicit robust 1.333 Hz voice-selective focal brain responses over superior temporal regions of individual participants. This response is virtually absent for sequences using frequency-scrambled sounds, but is clearly observed when voices are presented among sounds from musical instruments matched for pitch and harmonicity-to-noise ratio. Overall, our FPAS paradigm demonstrates that the human brain seamlessly categorizes human voices when compared to other sounds including matched musical instruments and that voice-selective responses are at least partially independent from low-level acoustic features, making it a powerful and versatile tool to understand human auditory categorization in general. Significance statementVoices are arguably among the most relevant sounds we hear in our everyday life, and several studies have corroborated the existence of regions in the human brain that respond preferentially to voices. However, whether this preference is driven by specific acoustic properties of voices or if it rather reflects a higher-level categorization response to voices is still under debate. We propose a new approach to objectively identify rapid automatic voice-selective responses with frequency tagging and electroencephalographic recordings. In four minutes of recording only, we recorded robust voice-selective responses independent from low-level acoustic cues, making this approach highly promising for studying auditory perception in children and clinical populations.

neuroscience↗

bioRxiv2017

Neuronal populations in the occipital cortex of the blind synchronize to the temporal dynamics of speech

The occipital cortex of early blind individuals (EB) activates during speech processing, challenging the notion of a hard-wired neurobiology of language. But, at what stage of speech processing do occipital regions participate in EB?Here we demonstrate that parieto-occipital regions in EB enhance their synchronization to acoustic fluctuations in human speech in the theta-range (corresponding to syllabic rate), irrespective of speech intelligibility. Crucially, enhanced synchronization to the intelligibility of speech was selectively observed in primary visual cortex in EB, suggesting that this region is at the interface between speech perception and comprehension. Moreover, EB showed overall enhanced functional connectivity between temporal and occipital cortices sensitive to speech intelligibility and altered directionality when compared to the sighted group. These findings suggest that the occipital cortex of the blind adopts an architecture allowing the tracking of speech material, and therefore does not fully abstract from the reorganized sensory inputs it receives.

neuroscience↗