Maternal immune activation alters infant attentional processing in a nonhuman primate model.

Maternal infection during pregnancy has been linked to the emergence of neurodevelopmental disorders. Preclinical animal models of maternal immune activation (MIA) have provided critical mechanistic links between maternal cytokines and alterations in offspring brain and behavioral development. While most preclinical work on MIA used rodent models, nonhuman primate (NHP) models have strong translational potential due to their greater similarity with humans. Previous NHP MIA models have replicated rodent findings of atypical offspring behavior emerging as animals mature, but few studied MIA-induced alterations in infancy. Here, we present a unique contribution on early milestones of attention in males using a rhesus monkey NHP MIA model. During an assessment of imitation conducted at 1 week-old, MIA-exposed offspring deviated from species-typical abilities to imitate social signals from human demonstrators. During a visual paired comparison task at 1 month, MIA-exposed offspring looked longer at novel abstract stimuli than control animals. A similar response was observed at 3-4 months when MIA-exposed offspring looked longer at novel monkey faces than control animals. The atypical response to novel social stimuli exhibited by MIA-exposed offspring appears contingent on how different the novel stimuli looked compared to the familiar stimuli, where MIA animals looked longer at easy discriminations compared to control animals. These results indicate that attentional processes in MIA-exposed offspring may be disrupted early in development, potentially resulting in longer visual stimuli processing times. Disruption of early attentional processes in the NHP MIA model may provide translational insights to identify children impacted by gestational exposure to maternal infections.