Behavioral effects of repetitive exposure to brief environmental enrichment in wistar rats

Environmental enrichment and deprivation are well-studied intervention models that impact sensory-motor experiences and lead to a range of behavioral, neural, and molecular effects in rodents. Enriched environments often boost cognitive functions, modify affective behaviors, and help alleviate neurological pathologies through various plasticity processes. In contrast, social isolation typically leads to adverse effects on the cognitive and emotional systems of rodents. These environmental conditions are often investigated under either short-term or prolonged exposures. Here, I investigated the behavioral and neural consequences of intermittent enrichment or isolation. I used twenty-four Wistar rats, dividing them into three groups as enriched (EC), impoverished (IC), and standard condition (SC). The 8-week-long protocol involved moving EC rats to enriched cages and IC rats to individual isolation cages for two days after a five-day period in standard housing. As a result, EC rats exhibited behavioral despair while it produced a profound anxiolytic effect. Intermittent enrichment transiently improved spatial memory, which was not maintained in subsequent trials or the probe test of Morris water maze. Immunohistochemical analysis of parvalbumin (PV) indicated fewer parvalbumin-immunopositive (PV+) cells in the CA1 region of IC rats compared to the EC and SC groups. IC rats also had reduced PV+ cells in the CA3 and dentate gyrus as compared to EC rats. No differences in PV+ cell counts were noted in the lateral or basolateral amygdala. These results highlight that intermittent periods of enrichment and deprivation are sufficient to induce significant behavioral and neural changes.