在有玩伴或很多玩具的环境下成长的儿童,脑功能更加活跃,记忆力和学习能力也会提高。日本科学家经动物实验发现,这或许是由于较多的外界刺激能使脑神经细胞内驱动蛋白增加,促进突触形成,令大脑更活跃。
东京大学研究人员在美国科学杂志《神经元》上报告说,他们在一个箱子中放置了各种玩具,将15只小鼠放到里面饲养了4周时间,同时在另一个没有放置任何玩具的箱子里饲养了3只小鼠。为考察两组小鼠的记忆力和学习能力,研究人员让小鼠在游泳池中反复游泳,记录它们到达泳池中“小岛”的时间。他们发现,在刺激较多的环境中生活的小鼠,随着游泳次数的增多,速度提升得更快。
在调查了两组小鼠脑部神经细胞的状态和蛋白质的作用后,研究人员发现,在刺激较多的环境中生活的小鼠,负责运送谷氨酸等神经传导物质的驱动蛋白“KIF1A”增加,且作用更加活跃,作为神经细胞结合点的突触也增加了。
研究人员通过基因操作,减少小鼠脑内的“KIF1A”,结果发现即使在刺激很多的环境下培养,小鼠的学习能力也不会提高。
研究人员认为,这项研究有助于解释为何拥有玩伴或玩具等会让儿童更聪明,并且对研究改善记忆和学习能力的方法也有所帮助。(生物谷 bioon.com)
doi: 10.1016/j.neuron.2011.12.020
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Motor Protein KIF1A Is Essential for Hippocampal Synaptogenesis and Learning Enhancement in an Enriched Environment
Makoto Kondo, Yosuke Takei, Nobutaka Hirokawa
Environmental enrichment causes a variety of effects on brain structure and function. Brain-derived neurotrophic factor (BDNF) plays an important role in enrichment-induced neuronal changes; however, the precise mechanism underlying these effects remains uncertain. In this study, a specific upregulation of kinesin superfamily motor protein 1A (KIF1A) was observed in the hippocampi of mice kept in an enriched environment and, in hippocampal neurons in vitro, BDNF increased the levels of KIF1A and of KIF1A-mediated cargo transport. Analysis of Bdnf+/ and Kif1a+/ mice revealed that a lack of KIF1A upregulation resulted in a loss of enrichment-induced hippocampal synaptogenesis and learning enhancement. Meanwhile, KIF1A overexpression promoted synaptogenesis via the formation of presynaptic boutons. These findings demonstrate that KIF1A is indispensable for BDNF-mediated hippocampal synaptogenesis and learning enhancement induced by enrichment. This is a new molecular motor-mediated presynaptic mechanism underlying experience-dependent neuroplasticity.