Piazza, E. A. | bioRxiv Science

bioRxiv2018

Infant and adult brains are coupled to the dynamics of natural communication

Infancy is the foundational period for learning from adults, and the dynamics of the social environment have long been proposed as central to childrens development. Here we reveal a novel, highly naturalistic approach for studying live interactions between infants and adults. Using functional near-infrared spectroscopy (fNIRS), we simultaneously and continuously measured the brains of infants (9-15 months) and an adult while they communicated and played with each other in real time. We found that time-locked neural coupling within dyads was significantly greater when they interacted with each other than with control individuals. In addition, we found that both infant and adult brains continuously tracked the moment-to-moment fluctuations of mutual gaze, infant emotion, and adult speech prosody with high temporal precision. This investigation advances what is currently known about how the brains and behaviors of infants both shape and reflect those of adults during real-life communication.

neuroscience↗

bioRxiv2016

Measuring speaker-listener neural coupling with functional near infrared spectroscopy

The present study investigates brain-to-brain coupling, defined as inter-subject correlations in the hemodynamic response, during natural verbal communication. We used functional near-infrared spectroscopy (fNIRS) to record brain activity of speakers telling stories and listeners comprehending audio recordings of these stories. Listeners brain activity was correlated with speakers with a delay. This between-brain correlation disappeared when verbal communication failed. We further compared the fNIRS and functional Magnetic Resonance Imaging (fMRI) recordings of listeners comprehending the same story and found a relationship between the fNIRS oxygenated-hemoglobin concentration changes and the fMRI BOLD in brain areas associated with speech comprehension. This correlation between fNIRS and fMRI was only present when data from the same story were compared between the two modalities and vanished when data from different stories were compared; this cross-modality consistency further highlights the reliability of the spatiotemporal brain activation pattern as a measure of story comprehension. Our findings suggest that fNIRS is a powerful tool for investigating brain-to-brain coupling during verbal communication. As fNIRS sensors are relatively low-cost and can even be built into wireless, portable, battery-operated systems, these results highlight the potential of broad utilization of this approach in everyday settings for augmenting communication and interaction.

neuroscience↗