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

Scientific Reports volume  14, Article number: 27650 (2024 ) Cite this article

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.

Recent technological advances have contributed to a sharp and significant rise in the usage of screens and other display devices1,2,3. Indeed, digital media can now be consumed via television and computer screens as well as portable phones and tablets, which may lead to excessive media exposure. Excessive media exposure refers to digital media usage that exceeds the exposure guidelines set by the American Academy of Pediatrics, which recommend eliminating digital media exposure (except video-chatting) prior to the age of 2 and 1 h per day for children 2–5 years of age as well as avoiding fast-paced and distracting content4. Of note, children today are immersed in electronic technology shortly after birth as they now begin regularly watching television earlier than they did a couple of decades ago, and many new programs are geared towards young infants5,6,7,8. Since children’s programming contains lots of lights, color, and sounds, this may constitute a form of sensory overstimulation (SOS) during early life, especially in cases of prolonged viewing (i.e., exposure)9. Importantly, human studies have found a link between overstimulation in infancy and subsequent deficits in cognition and attention such as increased impulsivity, difficulty in concentration, reduced executive function, as well as delayed socioemotional skills10,11,12,13,14,15. Additionally, there is growing evidence indicating that excessive digital media exposure (i.e., screen time) is linked to detrimental mental health outcomes in children and adolescents, including greater risk for developing psychiatric disorders such as mood, anxiety, and autism spectrum-related disorders16,17,18,19,20,21. Moreover, human studies have shown that greater durations of screen time exposure are correlated with the magnitude of impairments and risk for psychopathology10,15,22,23. These findings have raised concerns regarding the impact that excessive digital media exposure and SOS during early life may have on the developing brain as well as later life behavioral function. However, the mechanisms underlying these changes are poorly understood, underscoring an urgent need to understand how excessive digital media exposure, and the accompanying SOS this provides, affects trajectories of behavioral and brain development to influence later life mental health outcomes.

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