Environmental enrichment restores neurogenesis and rapid acquisition in aged rats

Abstract

Strategies combatting cognitive decline among the growing aging population are vital. We tested whether environmental enrichment could reverse age-impaired rapid spatial search strategy acquisition concomitantly with hippocampal neurogenesis in rats. Young (5–8 mo) and aged (20–22 mo) male Fischer 344 rats were pair-housed and exposed to environmental enrichment (n=7 young, 9 aged) or housed individually (n=7 young, 7 aged) for ten weeks. After five weeks, hidden platform trials (5 blocks of 3 trials; 15m IBI), a probe trial, and then visible platform trials (5 blocks of 3 trials; 15m IBI) commenced in the water maze. One week after testing, rats were given 5 daily bromodeoxyuridine (BrdU, 50mg/kg; i.p.) injections and perfused 4 weeks later to quantify neurogenesis. Although young rats outperformed aged rats, aged enriched rats outperformed aged individually-housed rats on all behavioral measures. Neurogenesis decreased with age but enrichment enhanced new cell survival, regardless of age. The novel correlation between new neuron number and behavioral measures obtained in a rapid water maze task among aged rats, suggests that environmental enrichment increases their ability to rapidly acquire and flexibly use spatial information along with neurogenesis.

Behavioral testing-related changes in the expression of Synapsin I and glucocorticoid receptors in standard and enriched aged Wistar rats

“…Rodent studies in which social, motor, cognitive and physical stimulation is provided have revealed that environmental enrichment (EE) in aged rats improves the spatial memory performance, increasing the ability to rapidly acquire a spatial memory task, along with a flexible use of spatial information (Baraldi et al, 2013;Harati et al, 2011;Speisman et al, 2013). Also, EE, in contrast to standard housing conditions, produces better indices of emotionality and faster adaptation to novel situations (Larsson et al, 2002;Zimmerman et al, 2001).…”

The effects of environmental enrichment on biochemical and metric parameters of aged rats

“…In the present study, the Aged EE group animals had brain mass greater than CG animals. In a recent study, Speisman and colleagues (2013) found that the maintenance of aged rats in an enriched cage contributes to improve the cognitive responses in cognitive tests and this occurs as an adaptation to neogenesis promoted by EE (SPEISMAN et al , 2013). Another recent study, comparing the effects of EE in adult and aged animals concluded that this type of housing contributes to promoting improvements in cognitive test response, although it promotes brain changes in different regions (MENDES et al, 2013).…”

Activité aérobie et environnement enrichi : perspectives pour le patient Alzheimer

“…Aussi, l'EE ne renverse pas les effets du vieillissement sur la différentiation neurale. La majorité des nouvelles cellules expriment un phénotype neuronal et en minorité un phénotype gliale [29]. Les études comparants rongeurs âgés et modèles de la MA confirment la baisse accrue du renouvellement cellulaire des populations malades [30].…”