Social EEG: A novel neurodevelopmental approach to studying brain-behavior links and brain-to-brain synchrony during naturalistic toddler-parent interactions

Getting closer to social interactions using electroencephalography in developmental cognitive neuroscience

The field of developmental cognitive neuroscience is advancing rapidly, with large-scale, population-wide, longitudinal studies emerging as a key means of unraveling the complexity of the developing brain and cognitive processes in children. While numerous neuroscientific techniques like functional magnetic resonance imaging (fMRI), functional near-infrared spectroscopy (fNIRS), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS) have proved advantageous in such investigations, this perspective proposes a renewed focus on electroencephalography (EEG), leveraging underexplored possibilities of EEG. In addition to its temporal precision, low costs, and ease of application, EEG distinguishes itself with its ability to capture neural activity linked to social interactions in increasingly ecologically valid settings. Specifically, EEG can be measured during social interactions in the lab, hyperscanning can be used to study brain activity in two (or more) people simultaneously, and mobile EEG can be used to measure brain activity in real-life settings. This perspective paper summarizes research in these three areas, making a persuasive argument for the renewed inclusion of EEG into the toolkit of developmental cognitive and social neuroscientists.

Investigating mother-child inter-brain synchrony in a naturalistic paradigm: A functional near infrared spectroscopy (fNIRS) hyperscanning study

Successful social interactions between mothers and children are hypothesised to play a significant role in a child's social, cognitive and language development. Earlier research has confirmed, through structured experimental paradigms, that these interactions could be underpinned by coordinated neural activity. Nevertheless, the extent of neural synchrony during real-life, ecologically valid interactions between mothers and their children remains largely unexplored. In this study, we investigated mother-child inter-brain synchrony using a naturalistic free-play paradigm. We also examined the relationship between neural synchrony, verbal communication patterns and personality traits to further understand the underpinnings of brain synchrony. Twelve children aged between 3 and 5 years old and their mothers participated in this study. Neural synchrony in mother-child dyads were measured bilaterally over frontal and temporal areas using functional Near Infra-red Spectroscopy (fNIRS) whilst the dyads were asked to play with child-friendly toys together (interactive condition) and separately (independent condition). Communication patterns were captured via video recordings and conversational turns were coded. Compared to the independent condition, mother-child dyads showed increased neural synchrony in the interactive condition across the prefrontal cortex and temporo-parietal junction. There was no significant relationship found between neural synchrony and turn-taking and between neural synchrony and the personality traits of each member of the dyad. Overall, we demonstrate the feasibility of measuring inter-brain synchrony between mothers and children in a naturalistic environment. These findings can inform future study designs to assess inter-brain synchrony between parents and pre-lingual children and/or children with communication needs.

Communicative signals during joint attention promote neural processes of infants and caregivers

Communicative signals such as eye contact increase infants' brain activation to visual stimuli and promote joint attention. Our study assessed whether communicative signals during joint attention enhance infant-caregiver dyads' neural responses to objects, and their neural synchrony. To track mutual attention processes, we applied rhythmic visual stimulation (RVS), presenting images of objects to 12-month-old infants and their mothers (n = 37 dyads), while we recorded dyads' brain activity (i.e., steady-state visual evoked potentials, SSVEPs) with electroencephalography (EEG) hyperscanning. Within dyads, mothers either communicatively showed the images to their infant or watched the images without communicative engagement. Communicative cues increased infants' and mothers' SSVEPs at central-occipital-parietal, and central electrode sites, respectively. Infants showed significantly more gaze behaviour to images during communicative engagement. Dyadic neural synchrony (SSVEP amplitude envelope correlations, AECs) was not modulated by communicative cues. Taken together, maternal communicative cues in joint attention increase infants' neural responses to objects, and shape mothers' own attention processes. We show that communicative cues enhance cortical visual processing, thus play an essential role in social learning. Future studies need to elucidate the effect of communicative cues on neural synchrony during joint attention. Finally, our study introduces RVS to study infant-caregiver neural dynamics in social contexts.

Caregiver-child interaction as an effective tool for identifying autism spectrum disorder: evidence from EEG analysis

BACKGROUND

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder that affects individuals across their lifespan. Early diagnosis and intervention are crucial for improving outcomes. However, current diagnostic methods are often time-consuming, and costly, making them inaccessible to many families. In the current study, we aim to test caregiver-child interaction as a potential tool for screening children with ASD in clinic.

METHODS

We enrolled 85 preschool children (Mean age: 4.90 ± 0.65 years, 70.6% male), including ASD children with or without developmental delay (DD), and typical development (TD) children, along with their caregivers. ASD core symptoms were evaluated by Childhood Autism Rating Scale (CARS) and Autism Diagnostic Observation Schedule-Calibrated Severity Scores (ADOS-CSS). Behavioral indicators were derived from video encoding of caregiver-child interaction, including social involvement of children (SIC), interaction time (IT), response of children to social cues (RSC), time for caregiver initiated social interactions (GIS) and time for children initiated social interactions (CIS)). Power spectral density (PSD) values were calculated by EEG signals simultaneously recorded. Partial Pearson correlation analysis was used in both ASD groups to investigate the correlation among behavioral indicators scores and ASD symptom severity and PSD values. Receiver operating characteristic (ROC) analysis was used to describe the discrimination accuracy of behavioral indicators.

RESULTS

Compared to TD group, both ASD groups demonstrated significant lower scores of SIC, IT, RSC, CIS (all p values < 0.05), and significant higher time for GIS (all p values < 0.01). SIC scores negatively correlated with CARS (p = 0.006) and ADOS-CSS (p = 0.023) in the ASD with DD group. Compared to TD group, PSD values elevated in ASD groups (all p values < 0.05), and was associated with SIC (theta band: p = 0.005; alpha band: p = 0.003) but not IQ levels. SIC was effective in identifying both ASD groups (sensitivity/specificity: ASD children with DD, 76.5%/66.7%; ASD children without DD, 82.6%/82.2%).

CONCLUSION

Our results verified the behavioral paradigm of caregiver-child interaction as an efficient tool for early ASD screening.

Mother-child inter-brain synchrony during a mutual visual search task: A study of feedback valence and role

Parent and child have been shown to synchronize their behaviors and physiology during social interactions. This synchrony is an important marker of their relationship quality and subsequently the child's social and emotional development. Therefore, understanding the factors that influence parent-child synchrony is an important undertaking. Using EEG hyperscanning, this study investigated brain-to-brain synchrony in mother-child dyads when they took turns performing a visual search task and received positive or negative feedback. In addition to the effect of feedback valence, we studied how their assigned role, i.e., observing or performing the task, influenced synchrony. Results revealed that mother-child synchrony was higher during positive feedback relative to negative feedback in delta and gamma frequency bands. Furthermore, a main effect was found for role in the alpha band with higher synchrony when a child observed their mother performing the task compared to when the mother observed their child. These findings reveal that a positive social context could lead a mother and child to synchronize more on a neural level, which could subsequently improve the quality of their relationship. This study provides insight into mechanisms that underlie mother-child brain-to-brain synchrony, and establishes a framework by which the impact of emotion and task demand on a dyad's synchrony can be investigated.

From Recognizing Known Words to Learning New Ones: Comparing Online Speech Processing in Typically Developing and Late-Talking 2-Year-Olds

PURPOSE

This study examines online speech processing in typically developing and late-talking 2-year-old children, comparing both groups' word recognition, word prediction, and word learning.

METHOD

English-acquiring U.S. children, from the "When to Worry" study of language and social-emotional development, were identified as typical talkers (n = 67, M age = 27.0 months, SD = 1.4; Study 1) or late talkers (n = 30, M age = 27.0 months, SD = 2.0; Study 2). Children completed an eye-tracking task assessing their ability to recognize both nouns and verbs, to use verbs to predict an upcoming noun's referent, and to use verbs to infer the meaning of novel nouns.

RESULTS

Both typical and late talkers recognized nouns and verbs and used familiar verbs to predict the referents of upcoming nouns, whether the noun was familiar ("You can eat the apple") or novel ("You can eat the dax"). Late talkers were slower in using familiar nouns to orient to the target and were both slower and less accurate in using familiar verbs to identify the upcoming noun's referent. Notably, however, both groups learned and retained novel word meanings with similar success.

CONCLUSIONS

Late talkers demonstrated slower lexical processing, especially for verbs. Yet, their success in using familiar verbs to learn novel nouns suggests that, as a group, their slower processing did not impair word learning in this task. This sets the foundation for future work investigating whether these measures predict later language outcomes and can differentiate late talkers with transient delays from those with language disorders.

Envisioning translational hyperscanning: how applied neuroscience might improve family-centered care

From the very beginning of their life, human beings are immersed in a social and interactive environment that contributes to shaping their social and cognitive development under typical and at-risk conditions. In order to understand human development in its bidirectional relationship with the social environment, we need to develop a 'complexity-sensitive' approach in neuroscience. Recent advances have started to do so with the application of hyperscanning techniques which involve recording adult and child neural activity simultaneously and highlighting the presence of similar patterns of brain activity in the dyad. Numerous studies focused on typically developing children have been published in recent years with the application of this technique to different fields of developmental research. However, hyperscanning techniques could also be extremely beneficial and effective in studying development in atypical and clinical populations. Such application, namely translational hyperscanning, should foster the transition toward a two-brain translational neuroscience. In this paper, we envision how the application of hyperscanning to atypical and clinical child populations can inform family-centered care for children and their parents.