Table 1.
Effects of environmental enrichment on neurobiology and behavior.
| Study’s primary objective | Animal species/strain | EE methods | Frequency of changing EE method | Protein/behavioral parameters investigated | Significant findings | Reference |
|---|---|---|---|---|---|---|
| • Effects of EE on neurodegeneration during AD | • AD11 mice | • Large cages with wire mesh lid, several food hoppers, running wheel and objects of different shapes (tunnels, shelters, stairs, boxes) | • Once per week | • Visual object recognition test | • ↑ Visual object recognition memory and spatial memory | Berardi et al. (2007) |
| • Morris water maze test | • ↓ Aβ deposition in hippocampus | |||||
| • IHC | • ↓ Progression of neurodegeneration | |||||
| • Effects of long-term EE on hippocampal neurogenesis | • 10 months old female C57BL/6 mice | • Large cages, with re-arrangeable set of plastic tubes, a running wheel, nesting material, and toys | – | • Behavioral testing with Activity chamber, Rotarod, and Water maze | • Fivefold increase in hippocampal neurogenesis in enriched environment | Kempermann et al. (2002) |
| • IHC and IF for lipofuscin deposits in neurons | • ↑ Learning, exploratory behavior, and locomotor activity | |||||
| • ↓ Lipofuscin deposits in the dentate gyrus | ||||||
| • Effects of environmental complexity on spatial abilities, dendritic arborization, and spine density | • Wistar rat (21 days old) | • Ten rats in a large cage of two levels connected by ramps, containing wood shavings, a running wheel, a shelter, plastic colored toys, and constructions | • Once a week | • Full-baited maze procedure and forced-choice procedure, performed in a radial maze | • ↑ Performance in the Radial maze and Morris water maze tasks | Leggio et al. (2005) |
| • Morris water maze | • ↑ Dendritic arborization and spine density in layer-III parietal pyramidal neurons | |||||
| • In vivo Golgi-like filling of the neurons for the visualization of dendritic arborization | ||||||
| • Influence of EE on neurotrophins levels in the cerebellum | • Adult male Wistar rats | • 10 rats in a large cage with two levels, connected by ramps, contain wood shavings, a running wheel, a shelter, plastic colored toys, and constructions | • Twice per week | • Determination of BDNF and NGF in all brain regions using ELISA | • ↑ BDNF levels in the cerebellum, frontal cortex and hippocampus | Angelucci et al. (2009) |
| • ↓ BDNF levels in the striatum | ||||||
| • ↑ NGF levels in the cerebellum and striatum | ||||||
| • No significant change in NGF levels in the frontal cortex and hippocampus | ||||||
| • Effects of EE on the neurogenesis and the extracellular concentrations of glutamate and GABA in the hippocampus | • Male Wistar rats of 2 and 25 months | • Two running wheels, a re-arrangeable set of plastic tunnels, an elevated platform, toys | • Every 3–4 days | • Water maze test | • ↑ Spatial memory performance | Segovia et al. (2006) |
| • Neurogenesis in the dentate gyrus of hippocampus using BrdU labeling | • ↑ Hippocampal neurogenesis in both young and aged enriched rats | |||||
| • Glutamate and GABA concentration in CA3 region of hippocampus using microdialysis probes | • ↓ Hippocampal neurogenesis in control rats | |||||
| • No effect of EE on basal concentration of Glutamate and GABA in young rats | ||||||
| • ↑ Basal glutamate and GABA concentration in old rats | ||||||
| • Effects of ageing and EE on synaptic plasticity | • Male Fischer rats | • Large cages furnished with various toys and small constructions | – | • Electron microscopic morphometry for the analyses of density and sizes of synapses | • ↓ Synaptic vesicle density with age | Nakamura et al. (1999) |
| • EE restored age-related loss of synaptophysin |
EE, environmental enrichment; AD, Alzheimer’s disease; IHC, immunohistochemistry; Aβ, amyloid-β; IF, immunofluorescence; BDNF, rain-derived neurotrophic factor; NGF, nerve growth factor; ELISA, enzyme linked immunosorbent assay; BrdU, bromodeoxyuridine; GABA, gamma-amino butyric acid; CA, Cornu Ammonis.