Parent-Infant Interpersonal Neural Synchronization and Social Gaze Direction during the Face-to-Face Still-Face Paradigm

Parent-infant social interactions and the corresponding brain activities is associated to sociocognitive development and this investigation is crucial for enhancing the quality of communication in parent-infant daily lives. Our study sought to understand how Interpersonal Neural Synchronization (INS) is affected by disruptions in parent-infant interactions, specifically focusing on how the INS in the theta band is associated to infant behavior (specifically gaze and emotional state) before and after the disruption. We conducted a study using the Face-to-Face Still-Face (FFSF) paradigm with 20 parent-infant dyads to examine infant gaze and emotional state as behavioral variables and explore their relationship with INS in the theta band. We used hyperscanning technique, and infant behaviors were coded after the data acquisition. Our findings showed significant changes in infant behavior (gaze and emotional state) across the episodes of the FFSF paradigm. Specifically, we observed a significant association between gaze and INS during the play episode but not during the reunion episode. However, we did not find the same result in INS in the theta band when comparing the emotional state between these episodes. These findings suggest that disruptions in parent-infant interactions can significantly alter theta band synchronization and that understanding these changes is crucial for developing interventions in early developmental contexts.