Torasdotter M, Metsis M, Henriksson B G, Winblad B, Mohammed A H
Department of Clinical Neuroscience and Family Medicine, Karolinska Institute, Huddinge University Hospital, Sweden.
Behav Brain Res. 1998 Jun;93(1-2):83-90. doi: 10.1016/s0166-4328(97)00142-3.
Evidence for structural modifications in the brain following environmental changes have been provided during the last decades. The most pronounced alterations following environmental manipulations have been found in the visual cortex. These plastic changes are supposed to reflect reorganization of neuronal connections involved in postnatal development and adult adjustments of connections involved in sensori-perceptual processing and learning. Potential candidates to mediate these changes are neurotrophins. Nerve growth factor (NGF) has been associated with cognitive functions and shown to improve the performance of aged rats in spatial learning and memory task. In the central nervous system, NGF is of importance for development and maintenance of cholinergic neurons and atrophy of cholinergic neurons is strongly correlated with learning and memory impairments. Exposure to enriched environmental conditions improves learning and problem-solving ability and results in plastic changes in the brain. This study examined the effect of environmental enrichment on expression of NGF mRNA in the rat visual cortex and hippocampus. Rats housed in groups in a stimulus-rich environment for 30 days had significantly higher levels of NGF mRNA than rats housed individually in single cages without stimulus-enrichment. We have recently presented results showing higher levels of neurotrophin-3 (NT-3) mRNA and improved spatial learning following environmental enrichment, and suggest that an interplay involving the neurotrophins NGF and NT-3 may be mediating experience-induced structural changes.
在过去几十年里，已有证据表明环境变化会导致大脑结构发生改变。在环境操纵后，视觉皮层出现了最明显的变化。这些可塑性变化被认为反映了参与出生后发育的神经元连接的重组以及参与感觉-知觉处理和学习的连接在成年后的调整。介导这些变化的潜在候选者是神经营养因子。神经生长因子（NGF）与认知功能有关，并已证明能改善老年大鼠在空间学习和记忆任务中的表现。在中枢神经系统中，NGF对胆碱能神经元的发育和维持很重要，胆碱能神经元的萎缩与学习和记忆障碍密切相关。暴露于丰富的环境条件下可提高学习和解决问题的能力，并导致大脑发生可塑性变化。本研究考察了环境丰富化对大鼠视觉皮层和海马中NGF mRNA表达的影响。在刺激丰富的环境中群居饲养30天的大鼠，其NGF mRNA水平显著高于单独饲养在无刺激丰富化的单笼中的大鼠。我们最近发表的结果表明，环境丰富化后神经营养因子-3（NT-3）mRNA水平升高，空间学习能力改善，并表明涉及神经营养因子NGF和NT-3的相互作用可能介导了经验诱导的结构变化。
