Environmental enrichment reverses noise induced impairments in learning and memory associated with the hippocampus in female rats

Environmental enrichment (EE) has positive effects on brain function and behavior in both healthy and behaviorally impaired animals. In earlier studies, we showed that rats exposed to noise during early development exhibited deficits in learning and memory associated with the hippocampus. In this study, we investigated whether EE provided during adulthood can reverse such noise-induced impairments. We found that four weeks of EE substantially improved learning and memory in adult female rats exposed to noise during early development. The behavioral changes observed after EE were accompanied by the restoration of parvalbumin-positive (PV+) inhibitory interneurons in the hippocampal subregions. EE also reversed noise-induced reductions in hippocampal long-term potentiation (LTP) of synaptic connections, a mechanism essential for learning and memory processing. However, an enriched environment that lacked social interaction had little effect on restoring LTP in noise-exposed rats. These findings suggest that EE effectively mitigates hippocampal impairments that stem from early noise exposure, with social interaction playing a crucial role in this recovery process.