PDF(Pubmed)
Abstract：
Adult neurogenesis is a unique form of neuronal plasticity in which newly generated neurons are integrated into the adult dentate gyrus in a process that is modulated by environmental stimuli. Adult-born neurons can contribute to spatial memory, but it is unknown whether they alter neural representations of space in the hippocampus. Using in vivo two-photon calcium imaging, we find that male and female mice previously housed in an enriched environment, which triggers an increase in neurogenesis, have increased spatial information encoding in the dentate gyrus. Ablating adult neurogenesis blocks the effect of enrichment and lowers spatial information, as does the chemogenetic silencing of adult-born neurons. Both ablating neurogenesis and silencing adult-born neurons decreases the calcium activity of dentate gyrus neurons, resulting in a decreased amplitude of place-specific responses. These findings are in contrast with previous studies that suggested a predominantly inhibitory action for adult-born neurons. We propose that adult neurogenesis improves representations of space by increasing the gain of dentate gyrus neurons and thereby improving their ability to tune to spatial features. This mechanism may mediate the beneficial effects of environmental enrichment on spatial learning and memory.
摘要：
成人神经发生是神经元可塑性的一种独特形式，其中新产生的神经元在受环境刺激调节的过程中整合到成人齿状回中。成年出生的神经元可以促进空间记忆，但尚不清楚它们是否会改变海马体空间的神经表现。使用体内双光子钙成像，我们发现雄性和雌性小鼠以前生活在丰富的环境中，这引发了神经发生的增加，在齿状回中增加了空间信息编码。消融成人神经发生阻断了富集的作用并降低了空间信息，成年神经元的化学遗传沉默也是如此。消融神经发生和沉默成年神经元都会降低齿状回神经元的钙活性，导致位置特异性反应的幅度降低。这些发现与先前的研究相反，先前的研究表明对成年神经元具有主要抑制作用。我们建议成人神经发生通过增加齿状回神经元的增益来改善空间表示，从而提高其调整空间特征的能力。这种机制可能介导环境丰富对空间学习和记忆的有益影响。
