Biology subjects

Bayet, L.

Publications and source records attributed to Bayet, L..

5 recordsLinked to original sources

bioRxiv2026

Experience shapes infants' electrophysiological responses to faces from 3 to 9 months

The types of faces that infants see impact their developing ability to engage with and individuate people from familiar and unfamiliar social groups, a phenomenon known as perceptual narrowing. However, the neural mechanisms that underlie infants processing of different faces as a function of experience remain poorly understood. To address this gap, the present study analyzes electroencephalography data collected while 3-month-olds (N=24), 6-month-olds (N=26), and 9-month-olds (N=18) viewed female and male faces of a familiar or unfamiliar social group. Infants neural responses to faces differed by group familiarity from 3 months of age, with increased responses to the more familiar face types in early components (P1, N290), and to the more unfamiliar face types in later components (P400, Nc). Face sex and group familiarity interacted to shape N290 and P400 amplitudes at 3- and 9-months. Specifically, N290 amplitudes were greater in response to female faces of a familiar group at 3 months, and to male faces of a familiar group at 9 months. In contrast, P400 amplitudes were greater in response to male faces of an unfamiliar group at 3 months old, and greatest in response to both female faces of a familiar group and to male faces of an unfamiliar group at 9 months. Source reconstruction of the Nc revealed greater reconstructed current density in response to faces of an unfamiliar social group across all ages. These findings contribute to a growing body of knowledge examining how perceptual experiences shape infants understanding of their social world.

neuroscience↗

bioRxiv2025

Neonatal mimicry of caregivers at home: feasibility of an asynchronous online paradigm

While early life sets the stage for later learning, comparatively less is known about newborns cognition than that of older infants. A striking example is the lack of consensus regarding the extent to which newborns spontaneously mimic gestures, and whether such behavior drives bonding and learning. Despite the theoretical importance of these questions, practical challenges limit researchers ability to engage newborns in behavioral research. Webcam-based, asynchronous online studies have expanded developmental sciences capacity to reach older infants. However, such scalable and replicable methods have yet to be deployed with younger infants. Taking a commonly-used neonatal mimicry paradigm as a test case, we assessed the feasibility of leveraging an open-source online platform (Children Helping Science) for asynchronous research with 0-6-week-olds and their caregivers. Caregivers modeled face movements to their 4-45 days-old infants (N = 29, N = 17 included) while webcams filmed their infants responses; 13 dyads participated more than once (72 included test videos). There was preliminary, moderate evidence against group-level neonatal mimicry of caregivers tongue protrusions (Bayes Factor [~] [1/3]), and inconclusive evidence for or against mimicry of caregivers mouth openings ([1/3] < BF < 3). Simulations identified a target sample size for more conclusive evidence. Finally, we asked whether caregivers perceived their newborns behavior as imitative. Caregivers perceptions of mimicry reflected infants behaviors but did not align with an often-used metric of mimicry ("imitators"). These results demonstrate the feasibility of asynchronous online behavioral studies with newborns and provide a foundation for future research on neonatal mimicry of caregivers.x1

neuroscience↗

bioRxiv2021

Time-resolved multivariate pattern analysis of infant EEG data

Time-resolved multivariate pattern analysis (MVPA), a popular technique for analyzing magneto- and electro-encephalography (M/EEG) neuroimaging data, quantifies the extent and time-course by which neural representations support the discrimination of relevant stimuli dimensions. As EEG is widely used for infant neuroimaging, time-resolved MVPA of infant EEG data is a particularly promising tool for infant cognitive neuroscience. MVPA methods have recently been applied to common infant imaging methods such as EEG and fNIRS. In this tutorial, we provide and describe code to implement time-resolved, within-subject MVPA with infant EEG data. A pipeline for time-resolved MVPA based on linear SVM classification is described and implemented with accompanying code in both Matlab and Python. Results from a test dataset indicated that in both infants and adults this method reliably produced above chance classification accuracy. Extensions of the core pipeline are presented including both geometric- and accuracy-based representational similarity analysis, implemented in Python. Common choices of implementation are presented and discussed. As the amount of artifact-free EEG data contributed by each participant is lower in studies of infants than in studies of children and adults, we also explore and discuss the impact of varying participant-level inclusion thresholds on resulting MVPA findings in these datasets.

neuroscience↗

bioRxiv2020

Neural responses to happy, fearful and angry faces of varying identities in 5- and 7-month-old infants

Facial emotion processing is an important social skill that develops throughout infancy and early childhood. Here we investigate the neural underpinnings of the ability to process facial emotion across changes in facial identity in cross-sectional groups of 5- and 7-month-old infants. We simultaneously measured neural metabolic, behavioral, and autonomic responses to happy, fearful, and angry faces of different female models using functional near-infrared spectroscopy (fNIRS), eye-tracking, and heart rate measures. We observed significant neural activation to these facial emotions in a distributed set of frontal and temporal brain regions, and longer looking to the mouth region of angry faces compared to happy and fearful faces. No differences in looking behavior or neural activations were observed between 5- and 7-month-olds, although several exploratory, age-independent associations between neural activations and looking behavior were noted. Overall, these findings suggest more developmental stability than previously thought in responses to emotional facial expressions of varying identities between 5- and 7-months of age.

neuroscience↗

bioRxiv2020

Temporal dynamics of visual representations in the infant brain

Tools from computational neuroscience have facilitated the investigation of the neural correlates of mental representations. However, access to the representational content of neural activations early in life has remained limited. We asked whether patterns of neural activity elicited by complex visual stimuli (animals, human body) could be decoded from EEG data gathered from 12-15-month-old infants and adult controls. We assessed pairwise classification accuracy at each time-point after stimulus onset, for individual infants and adults. Classification accuracies rose above chance in both groups, within 500 ms. In contrast to adults, neural representations in infants were not linearly separable across visual domains. Representations were similar within, but not across, age groups. These findings suggest a developmental reorganization of visual representations between the second year of life and adulthood and provide a promising proof-of-concept for the feasibility of decoding EEG data within-subject to assess how the infant brain dynamically represents visual objects.

neuroscience↗