Meconi Alicia, Lui Erika, Marrone Diano F
Department of Psychology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada.
Department of Psychology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada; McKnight Brain Institute, University of Arizona, Tucson, AZ 85724, USA.
Neurosci Lett. 2015 Aug 31;603:66-70. doi: 10.1016/j.neulet.2015.07.029. Epub 2015 Jul 26.
The dentate gyrus (DG) plays a critical role in memory formation and maintenance. Fitting this specialized role, the DG has many unique characteristics. In addition to being one of the few places in which new neurons are continually added in adulthood, the region also shows a unique long-term sustained transcriptional response of the immediate-early gene Arc to sensory input. Although we know that adult-generated granule cells are reliably recruited into behaviorally-driven neuronal network, it remains unknown whether they display robust late-phase sustained transcription in response to activity like their developmentally-generated counterparts. Since this late-phase of transcription is required for enduring plasticity, knowing if sustained transcription appears as soon as these cells are incorporated provides information on their potential for plasticity. To address this question, adult F344 rats were injected with BrdU (50mg/kg/day for 5 days) and 4 weeks later explored a novel environment. Arc expression in both BrdU- and BrdU+ neurons was determined 0.5h, 1h, 2h, 6h, 8h, 12h, or 24h following this behavior. Recently-generated granule cells showed a robust sustained Arc expression following a discrete behavioral experience. These data provide information on a potential mechanism to sculpt the representations of events occurring within hours of each other to create uncorrelated representations of episodes despite a highly excitable population of neurons.
齿状回（DG）在记忆形成和维持中起着关键作用。为适应这一特殊作用，DG具有许多独特特征。除了是成年期持续产生新神经元的少数部位之一外，该区域还对感觉输入表现出立即早期基因Arc独特的长期持续转录反应。尽管我们知道成年产生的颗粒细胞能可靠地被招募到行为驱动的神经网络中，但它们是否像发育产生的对应细胞一样，在对活动的反应中表现出强大的晚期持续转录仍不清楚。由于这种转录后期对于持久的可塑性是必需的，了解这些细胞一旦被纳入是否就会出现持续转录，可提供有关其可塑性潜力的信息。为解决这个问题，给成年F344大鼠注射BrdU（50mg/kg/天，共5天），4周后让其探索一个新环境。在该行为后的0.5小时、1小时、2小时、6小时、8小时、12小时或24小时，测定BrdU和BrdU+神经元中的Arc表达。最近产生的颗粒细胞在离散的行为经历后表现出强大的持续Arc表达。这些数据提供了一种潜在机制的信息，该机制可塑造在数小时内相继发生的事件的表征，以创建不相关的情节表征，尽管存在高度兴奋的神经元群体。
