Table 1.
Structural and functional effects of environmental enrichment (EE).
| Sample | EE condition | Functional Effects (behavioral effects) | Structural Effects (molecular and cellular effects) | Refs. | |
|---|---|---|---|---|---|
| Effects of EE on healthy rodents | |||||
| Wistar rats | EE from weaning for 2.5/3 months | Precocious development of spatial cognitive map; enhanced spatial memory and cognitive flexibility | Increases dendritic length and spine density in frontal and parietal pyramidal neuron apical and basal arborizations; synaptogenesis; increases of BDNF levels in the hippocampus and cerebellum | [14, 23, 35–37, 40] | |
| Wistar rats C57BL/6J mice |
Maternal and paternal EE: a transgenerational model | In pups: accelerated acquisition of complex motor behaviors; decreased anxiety-related behaviors | In pups: high expression of neurotrophin in cerebellar and striatal areas; low ACTH levels | [38–41] | |
|
| |||||
| Neuroprotective effects of EE on neurodegeneration | |||||
| Neurodegenerative disorders | HD mouse models | Running exercise about from 4 weeks of age | Partially delayed onset of motor symptoms and cognitive deficits (memory/executive functions) | Altered BDNF mRNA levels | [10, 15, 42–45] |
| EE about from 4 weeks of age | Delayed onset of motor symptoms and cognitive deficits (memory/executive functions) | Decreased cortical and striatal volume loss; ameliorated deficit in neurogenesis; increased neurotrophin expression; enhanced CB1 receptor levels | |||
| PD mouse models | Running exercise from 6 weeks | Attenuated motor impairment, reduced anxiety behavior | Decreased loss of striatal DA | [10, 15, 46–49] | |
| AD mouse/rat models | Intensive locomotor training | Increases performances in spatial memory tasks | Decreased beta-amyloid plaques | [10, 15, 24–27, 50–57, 62] | |
| EE from weaning for 2.5/3 months; EE for 2 months at different age | Enhanced spatial memory and executive functions (cognitive flexibility) | Decreased beta-amyloid plaques; increased levels of neurotrophic substances; increased spine number and density in pyramidal neurons | |||
| Aging | EE and locomotor training in middle age | Preservation of spatial abilities in old age | Changes in hippocampal astrocytes; hippocampal neurogenesis | [58–61] | |
EE refers to a complex stimulation of experiences. BDNF: brain-derived neurotrophic factor; NGF: nerve growth factor; ACTH: adrenocorticotropic hormone; HD: huntington's disease; PD: parkinson's disease; AD: alzheimer's disease; DA: dopamine.