Parent-child dyads with greater parenting stress exhibit less synchrony in posterior areas and more synchrony in frontal areas of the prefrontal cortex during shared play.

Parent-child dyads who are mutually attuned to each other during social interactions display interpersonal synchrony that can be observed behaviorally and through the temporal coordination of brain signals called interbrain synchrony. Parenting stress undermines the quality of parent-child interactions. However, no study has examined synchrony in relation to parenting stress during everyday shared play. The present fNIRS study examined the association between parenting stress and interbrain synchrony in the prefrontal cortex (PFC) of 31 mother-child and 29 father-child dyads while they engaged in shared play for 10 min. Shared play was micro-analytically coded into joint and non-joint segments. Interbrain synchrony was computed using cross-correlations over 15-, 20-, 25-, 30- and 35-s fixed-length windows. Findings showed that stressed dyads exhibited less synchrony in the posterior right cluster of the PFC during joint segments of play, and, contrary to expectations, stressed dyads also showed greater synchrony in the frontal left cluster. These findings suggest that dyads with more parenting stress experienced less similarities in brain areas involved in emotional processing and regulation, whilst simultaneously requiring greater neural entrainment in brain areas that support task management and social-behavioral organization in order to sustain prolonged periods of joint interactions.