How environmental enrichment influences conditioned taste aversion: A case of behavioral tagging

Abstract

Exposure to environmental enrichment (EE) has demonstrated a remarkable ability to modulate cognitive processes. These effects have been associated with brain-derived neurotrophic factor (BDNF), a protein recognized for regulating synaptic plasticity in the adult brain. Previous research from our group revealed that exposure to EE prior to the acquisition of a strong form of conditioned taste aversion (CTA) weakens the aversive response by restoring BDNF levels in the insular cortex (IC), a region in the temporal lobe involved in multimodal sensory integration and learning and memory processes. The behavioral tagging model offers a framework to explain how salient or novel events can strengthen weak memory traces encoded within critical time windows before or after the novel experience. However, to date, the effect of brief exposure to an enriched environment at the critical timeframe between the acquisition phase and the aversion test has not been fully clarified. The present study aimed to evaluate the effects of environmental enrichment on the strength of CTA memory, when the EE is presented during the period spanning from acquisition to aversion test. To do so, Wistar rats were exposed to environmental enrichment for seven days between the acquisition session and the CTA aversion test. Our results show for the first time that a brief exposure to an enriched environment can strengthen the aversive response of a weak CTA. Our results also show that the response strengthening is accompanied by a reduction in BDNF levels in the IC. These findings present evidence that an aversive memory response can be modified through innovative and complex behavioral manipulation, highlighting enriched environments as potential modulators of aversive memory within critical periods of memory processing.