Environmental Enrichment Results in Both Brain Connectivity Efficiency and Selective Improvement in Different Behavioral Tasks

Can the effects of environmental enrichment modulate BDNF expression in hippocampal plasticity? A systematic review of animal studies

“…Among the main findings of this review, 17 of the 32 selected articles used male rats or mice (Amaral, Vargas, Hansel, Izquierdo, & Souza, ; Bechara & Kelly, ; Birch, McGarry, & Kelly, ; Eckert & Abraham, ; Faherty, Kerley, & Smeyne, ; Iso, Simoda, & Matsuyama, ; Kondo, Takei, & Hirokawa, ; Lerch, ; Madronal et al, ; Novkovic, Heumann, & Manahan‐Vaughan, ; Rizzi, Bianchi, Guidi, Ciani, & Bartesaghi, ; Silva, Duarte, Lima, & Oliveira, ; Vedovelli et al, ; Viola et al, ; Xu et al, ; Zeleznikow‐Johnston, Burrows, Renoir, & Hannan, ; Zhang et al, ), 8 evaluated only females (Fabel et al, ; Hosseiny et al, ; Kobilo et al, ; Nilsson, Perfilieva, Johansson, Orwar, & Eriksson, ; Prusky, Reidel, & Douglas, ; Valero‐Aracama, Sauvage, & Yoshida, ; Williams et al, ; Ziv et al, ), 1 article used male and female mice (Melani, Chelini, Cenni, & Berardi, ) and 6 did not identify the sex of the animals used in the study (Catlow et al, ; Huang, Huang, Wu, & Boucheron, ; Li, Niu, Jiang, & Hu, ; Rampon et al, ; Sampedro‐Piquero et al, ; Schloesser, Lehmann, Martinowich, Manji, & Herkenham, ).…”

“…In addition to the associations between EE and cellular mechanisms, a correlation between the EE and the morphofunctional aspects of the other types of plasticity were observed in the hippocampus in 17 studies (Amaral et al, ; Birch et al, ; Eckert & Abraham, ; Faherty et al, ; Huang et al, ; Iso et al, ; Lerch, ; Li et al, ; Melani et al, ; Novkovic, Heumann, et al, ; Prusky et al, ; Rampon et al, ; Sampedro‐Piquero et al, ; Schloesser et al, ; Viola et al, ; Williams et al, ; Zeleznikow‐Johnston et al, ). Using nucleotide array analysis, one study verified that genes involved in cell signaling and apoptosis in the hippocampus in addition to genes involved in the formation of new synapses and the reorganization or elongation of existing synapses were expressed differently after EE; moreover, the expression of genes associated with neuronal excitability and NMDA receptors were changed after 3 hr and 6 hr of EE exposure per day and in the long term, EE altered the levels of mRNA‐associated genes during growth (Rampon et al, ).…”

“…Only five studies did not report the age of the animals used in the experimental procedures (Eckert & Abraham, ; Faherty et al, ; Li et al, ; Schloesser et al, ; Valero‐Aracama et al, ). The ages of the animals ranged from 3 to 5 months in 6 studies (Hosseiny et al, ; Kondo et al, ; Madronal et al, ; Melani et al, ; Sampedro‐Piquero et al, ; Vedovelli et al, ), and animals aged less than 3 months were used in 13 studies (Amaral et al, ; Birch et al, ; Kobilo et al, ; Lerch, ; Nilsson et al, ; Novkovic, Heumann, et al, ; Prusky et al, ; Rampon et al, ; Rizzi et al, ; Silva et al, ; Viola et al, ; Xu et al, ; Zhang et al, ). Only two articles used animals that were over the age of 5 months (Catlow et al, ; Zeleznikow‐Johnston et al, ).…”

“…The animals were exposed to EE for less than a month in six studies (Bechara & Kelly, ; Catlow et al, ; Eckert & Abraham, ; Huang et al, ; Li et al, ; Rampon et al, ). In most of the studies, the animals were exposed to EE for a period of 1–6 months (Amaral et al, ; Birch et al, ; Fabel et al, ; Faherty et al, ; Hosseiny et al, ; Iso et al, ; Kobilo et al, ; Madronal et al, ; Nilsson et al, ; Novkovic, Heumann, et al, ; Sampedro‐Piquero et al, ; Schloesser et al, ; Silva et al, ; Valero‐Aracama et al, ; Vedovelli et al, ; Viola et al, ; Williams et al, ; Xu et al, ; Zhang et al, ; Ziv et al, ).…”

“…The exchange and/or rearrangement of utensils was carried out at different frequencies. Utensil exchange and/or rearrangement was not reported in 13 articles (Amaral et al, ; Fabel et al, ; Iso et al, ; Kondo et al, ; Lerch, ; Madronal et al, ; Nilsson et al, ; Novkovic, Heumann, et al, ; Rizzi et al, ; Sampedro‐Piquero et al, ; Viola et al, ; Xu et al, ; Ziv et al, ). In eight studies, the exchange and/or rearrangement of the utensils occurred at a frequency of more than 1x/week (Huang et al, ; Li et al, ; Prusky et al, ; Rampon et al, ; Silva et al, ; Valero‐Aracama et al, ; Vedovelli et al, ; Williams et al, ).…”