Cortical patterns of social-emotional processing in early childhood: Electrophysiological responses to facial affect and familiarity in a Go-Nogo task

To date, little is known about the neural underpinnings of social-emotional processes in young children. The present study investigated the time course of children's event-related potential (ERP) responses to facial expression and personal familiarity, and the effect of emotional valence on ERP measures of inhibitory control. Dense-array EEG was collected from 48 4-to-6-year-old children who were presented with pictures of their mothers and strangers' happy and angry faces. ERPs were scored following face presentation and a subsequent cue signaling a Go or Nogo response. Following face presentation, early perceptual ERP components were larger for strangers' faces, suggesting facilitated rapid processing of personally important faces. A mid-latency frontocentral negativity was greatest for angry mothers' faces, indicating increased attentional monitoring and/or recognition memory evoked by an angry parent. Finally, a right-lateralized late positive component was largest for angry faces, suggesting extended processing of negatively-valenced social stimuli in general. Models of cortical generators suggested that early discrimination between familiar and unfamiliar faces was mediated by the ventromedial prefrontal cortex. Later activation in the ventromedial prefrontal cortex and temporal lobes was linked to individual differences in trait fearfulness and attentional control. Following the Go-Nogo response cue, the N2, a mid-latency scalp component, was larger in Nogo than Go trials and for angry than happy faces, possibly reflecting greater self-regulation required in those conditions. Source models for the N2 suggested that generators in the ventromedial prefrontal cortex, anterior temporal lobes, and dorsomedial prefrontal cortex contributed to the scalp results. The present study suggests that overlapping but differentiated networks for rapid and elaborative processing of important socio-affective information are established by 4-6 years. Moreover, the extended spatial and temporal distribution of components suggests a pattern of response to social stimuli in which more rapid processes may index personal familiarity, whereas temporally extended processes are sensitive to the affective valence of both familiar and unfamiliar faces.