Inter-neural co-regulation before and after an interactive perturbation in mother-infant dyads.

Hyperscanning techniques allow inter-neural synchrony (INS) estimation and represent an innovative approach to investigate neural processes underlying social exchanges. Electroencephalographic (EEG) studies showed that collaborative parent-infant social interactions might be characterized by varying levels of INS. Nonetheless, despite social mismatches are common occurrences in early interactions, limited research has focused on INS variations elicited by interactive perturbations. (1) to assess variations in INS before and after an experimentally-induced interactive perturbation; (2) to investigate the relationship between INS and behavioral coupling. Sixty-six dyads of 9-month-old infants and their mothers participated in the well-validated Face-to-Face Still-Face (FFSF) procedure combined with dual-EEG recordings. Infants and maternal behaviors were microanalytically coded and phase locking values (PLV) over frontal, central and posterior regions in the theta and alpha bands were computed from the dual-EEG recordings. A significant increase in alpha coupling emerged before and after perturbation. Conversely, a reduction in theta coupling was highlighted in the subgroup of female infants. Behavioral and EEG-based dyadic co-regulation in the theta band was evident only prior to the perturbation. This study highlights the role of alpha and theta wave coupling in response to parental unresponsiveness, with differential patterns emerging when the dyadic system is perturbated.