Sex-dependent effects of early life sensory overstimulation on later life behavioral function in rats

Children today are immersed in electronic technology shortly after birth as they now begin regularly watching television earlier than they did in the past. Many new programs geared towards infants contain lots of lights, color, and sounds, which may constitute a form of sensory overstimulation (SOS) that leads to cognitive and behavioral changes in children and adolescents. Here, we examined the impact of early life SOS exposure on later life behavioral and cognitive function in rodents by exposing developing male and female rats to excessive audiovisual stimulation from postnatal days (PND) 10-40 and assessing anxiety-like behavior, social motivation, compulsive behavior, and spatial learning/cognition from PND 50-60. To evaluate potential SOS effects on hypothalamic-pituitary-adrenal (HPA)-axis function, levels of the stress hormone corticosterone (CORT) were measured at 3 timepoints (e.g., PND 23, 41, 61) post-SOS exposure. Sensory overstimulated males exhibited reduced anxiety-like and compulsive behavior compared to controls, whereas females exhibited reduced social motivation but enhanced spatial learning/cognition compared to controls. No differences in baseline CORT levels were found at any age tested, suggesting no impact of early life SOS on later life basal HPA-axis function. Our results demonstrate sex-specific effects of early life SOS on distinct behavioral domains in early adult rats.