Cognitive Training and Enrichment Modulates Neural Plasticity and Enhances Cognitive Reserve in Aging Rats.

Objectives: Cognitive decline in non-pathological aging is widely prevalent among the aging population. The current study assessed the impact of cognitive training (Ct) with multiple modules targeting various facets of learning and memory and the additional influence of an enriched environment (Ct+ee) on hippocampal subfields of aging male rats.

Methods: Male Wistar rats aged 18 months were sorted into Control, Ct, and Ct+ee groups and were exposed to the respective modules for 30 days. Spontaneous behavioral tasks to assess working memory and recognition memory were performed. The hippocampal proper (CA1, CA3) and dentate gyrus (DG) neurons were analyzed for dendrite length, arborization, and spine density. The Synaptophysin, PSD 95 and BDNF, p53 and p-tau levels in the hippocampus were quantified.

Results: The Ct group and Ct+ee group performed significantly better than the control group in behavioural tasks and had improved dendrite profiles of DG and basal tree of CA1 region of hippocampus. The Ct+ee group had increased dendrite length, arborization, and spine density in CA1, CA3 and DG neurons. Ct and Ct+ee groups showed increased expression of synaptophysin, PSD95 and BDNF and decreased p53 and p-tau levels in the hippocampus.

Conclusion: Cognitive training modules targeting specific mnemonic functions and enriched environment with diverse cognitive stimulators had a comprehensive effect on the neuronal health augmenting the impoverished cognitive reserve in aging rats.