Childhood trauma predicts attenuated N170 responses to happy child faces: ERP Evidence of early perceptual gating deficits.

Maternal sensitivity to children's emotional cues is a fundamental determinant of healthy child development, yet childhood trauma can disrupt the neurobiological processes underlying this sensitivity, contributing to the intergenerational transmission of adversity. This study investigated how childhood trauma (CT) and trauma-specific reflective functioning (RF-T) influence the neural processing of children's emotional expressions. Using event-related potentials (ERPs) in a sample of mothers with histories of maltreatment (N = 30), we examined three functionally distinct stages: early structural encoding (N170), attentional allocation (P300), and sustained emotional engagement (LPP). Participants completed a passive viewing task involving child facial expressions (happy, fearful, angry) while EEG was recorded. Results revealed that higher CT significantly predicted attenuated N170 amplitudes specifically for happy child faces (β = -0.55, p = .006), indicating a selective disruption in the early perceptual encoding of positive socio-emotional cues. Conversely, CT did not affect P300 or LPP components, and RF-T showed no neural associations. These findings suggest that early adversity may recalibrate sensory gating to deprioritize social safety cues. Yet, preserved later evaluative processes indicate neurocognitive resilience. This dissociation identifies a bottleneck in maternal attunement and a targeted pathway for interventions to disrupt intergenerational trauma transmission.