Rapid engagement of salience and prefrontal systems during emotional processing in children: An MEG study

Children's ability to process emotional information is central for social development and for understanding risk factors for affective disorders. Prior neuroimaging studies have identified brain systems underlying emotional processing, but most have relied on functional MRI, which cannot capture rapid neural dynamics. Moreover, these studies utilized emotional stimulus sets with outdated, adult-focused content, which may not effectively engage children, thereby reducing sensitivity to developmental effects. Here, we used magnetoencephalography (MEG) to examine the spatiotemporal dynamics of emotional processing in children and adolescents. Fifty-seven participants viewed pleasant, unpleasant, and neutral pictures from the Nencki Affective Picture System (NAPS), a recent database with child-appropriate content. Source-reconstructed responses were analysed using cluster-based permutation tests. Both pleasant and unpleasant pictures elicited stronger activity than neutral ones in salience and prefrontal regions, including the insula and orbitofrontal cortex, as early as 50-100 ms. Unpleasant pictures evoked stronger and more sustained activity than pleasant pictures in salience and default mode network regions, consistent with negativity bias. Finally, developmental analyses revealed that younger children exhibited greater medial prefrontal response amplitude to pleasant than to unpleasant pictures between 650-700 ms post-stimulus, whereas older adolescents showed greater medial prefrontal response amplitude to unpleasant than to pleasant pictures during the same time window. Overall, these results suggest that children rapidly differentiate emotional from neutral input, prioritize negative information in salience and default mode network systems, and that age influences emotional processing in prefrontal and default mode network regions. Our findings clarify the timing of affective brain responses across development and inform pathways of risk for affective disorders.