Neural and Behavioral Correlates of Live Face-to-Face Interactions

About This Grant

Summary Recent interest in the neural correlates of naturalistic behaviors has increased the need for tools to acquire multimodal measures during real world contexts. Human faces in natural settings are primary sources of socially communicated information but are traditionally studied in non-interactive contexts. Faces not only carry the structural information that serves identification, but also communicate social cues driven by live and spontaneous dynamics that convey emotion, direct attention, and regulate eye-to-eye contact. However, this domain of live and natural interacting faces has not been widely studied due to the absence of reliable and validated measurement methods appropriate for observing such interaction under ecologically valid conditions. We address this knowledge gap here by proposing to establish a Social Interaction Suite (SIS) of synchronized neural and behavioral tools designed for measurements of cognitive networks associated with processing facial cues and their correlated behaviors exchanged in live social interactions. SIS is developed on a neural imaging platform based on functional near infrared spectroscopy (fNIRS), a head mounted optical imaging system, to acquire hemodynamic signals that originate from superficial cortex. This suite of tools will include simultaneous and synchronized electroencephalography (EEG), eye-tracking, pupillometry, facial feature tracking and associated emotive categorization, subjective responses (dial ratings), and physiological monitoring during live eye-to-eye contact and emotional contagion tasks. Prior studies of dyadic face interactions provide evidence that real faces engage specialized neural circuits beyond the well-known ventral stream face processing circuits and include right superior temporal gyrus (rSTG), supramarginal gyrus (rSMG) and angular gyrus (rAG). Eye-to-eye contact additionally engages regions in the dorsal parietal area, right somatosensory cortex (rSSAC). We aim to advance a theoretical framework for this interactive face and eye-contact model by testing the hypothesis that the live-face and the eye-to-eye contact systems are dissociable cortical pathways. Validation and characterization of the model will be performed by continuous transcranial brain stimulation (cTBS) to disrupt candidate regions in the live face processing systems at sites informed by the previous pilot fNIRS and behavioral data. Following the completion of the initial tool development and validation phase, the obtained results will be used in the application of functionally defined multi-electrode targeted transcranial direct current stimulation (tDCS) to test hypotheses related to up and down regulation of the dorsal parietal and lateral face processing regions. Successful manipulation of eye contact under excitatory and inhibitory tDCS stimulation of the dorsal region will extend our cTBS results and provide proof of concept for the application of neural modulation as a tool for facilitating social interaction.