Context differences in delta beta coupling are associated with neuroendocrine reactivity in infants.

Although evidence suggests that delta-beta coupling may provide a useful index of trait level cortico-subcortical cross talk in baseline contexts, there has been little work done to clarify the role of delta-beta coupling across contexts and in association with other physiological markers of emotion processing. We examined whether individual differences in coupling were visible across both positive and negative emotion-eliciting episodes during infancy (age 6 months). We also tested the convergence between measures of delta-beta coupling and neuroendocrine reactivity, which is also believed to index emotion processing. Patterns of coupling across emotion-eliciting episodes differed based on infants' levels of cortisol reactivity. Low cortisol-reactive infants largely did not show differences in coupling across emotion contexts while high cortisol-reactive infants showed greater coupling in non-fear contexts during baseline and fear episodes. Moreover, high cortisol-reactive infants showed greater coupling than low-reactive infants in non-positive episodes.