Chronic Inflammation is Associated with Neural Responses to Faces in Bangladeshi Children

Background: Early exposure to inflammation in childhood is increasingly recognized as one of the major factors that hinder millions of children worldwide from meeting their full developmental potential. The current study examined the association between systemic inflammation and children's neural responses to facial stimuli and explored if this activity mediated the relation between inflammation and cognitive outcomes.

Method: Two separate cohorts of children living in an urban slum in Dhaka, Bangladesh who are at high-risk for sustained inflammation were recruited in this study. The concentration of C-reactive protein (CRP) in blood samples served as our index of inflammation. Blood samples were collected once at 18 weeks for the younger (infant) cohort (N = 125) and at 6, 18, 40, 53, and 104 weeks for the older (toddler) cohort (N = 120). Event-related potentials (ERPs) were also recorded separately for the two cohorts: at 6 months for the younger cohort (N = 48) and at 36 months for the older cohort (N = 93), using a face-oddball paradigm in which standard and oddball faces were presented. Cognitive outcomes were evaluated with Mullen Scales of Early Learning (MSEL) at 27 months for the younger cohort (N = 98) and with Wechsler Preschool and Primary Scale of Intelligence (WPPSI) at 48 months for the older cohort (N = 124).

Results: For the older toddler cohort, the P400 and Nc amplitude differences between the two types of stimuli were found to be associated with the frequency of elevated CRP such that more episodes of elevated CRP corresponded to smaller P400 and Nc differences between the two conditions. In addition, the P400 and Nc differences were both found to mediate the relation between inflammation and performance IQ scores. For the younger infant cohort, the participants showed differentiated N290 response to the two types of stimuli, but no association between the ERP response and CRP concentration was found.

Conclusions: These findings suggest that chronic systemic inflammation has a long-term impact on children's brain functioning and cognitive development. The neural circuitries associated with social attention and recognition memory of faces may be potential pathways by which inflammation exerts its effect on cognitive development.