Developmental Scarcity Induces Sex Differences in Social Recognition and CA2 Perineuronal Nets.

Early-life adversity (ELA) has a lasting negative impact on social behavior in both humans and rodents. Sex differences exist in functional outcomes of postnatal stress, but underlying mechanisms remain incompletely explored. Using the limited bedding and nesting paradigm, a mouse model of developmental scarcity, we found sex differences in social behavior with adult males showing impaired social recognition and adult females showing intact social recognition with enhanced social novelty preference. Perineuronal nets (PNNs), specialized extracellular matrix structures, are known to inhibit developmental plasticity and are concentrated in the CA2 region of the hippocampus in adulthood. We found higher intensity of CA2 PNNs in adult males, but not adult females, after ELA. Focal degradation of the extracellular matrix in the CA2 region restored social recognition function in adult males previously subjected to early stress, suggesting that the effects of developmental adversity may be improved by targeted intervention in adulthood.