Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA.
Neuron. 2011 Jun 23;70(6):1128-42. doi: 10.1016/j.neuron.2011.04.027.
Efficient memory formation relies on the establishment of functional hippocampal circuits. It has been proposed that synaptic connections are refined by neural activity to form functional brain circuitry. However, it is not known whether and how hippocampal connections are refined by neural activity in vivo. Using a mouse genetic system in which restricted populations of neurons in the hippocampal circuit are inactivated, we show that inactive axons are eliminated after they develop through a competition with active axons. Remarkably, in the dentate gyrus, which undergoes neurogenesis throughout life, axon refinement is achieved by a competition between mature and young neurons. These results demonstrate that activity-dependent competition plays multiple roles in the establishment of functional memory circuits in vivo.
高效的记忆形成依赖于功能性海马回路的建立。有人提出，突触连接通过神经活动得到精炼，从而形成功能性大脑回路。然而，目前尚不清楚海马连接是否以及如何通过体内神经活动得到精炼。我们利用一种小鼠遗传系统，该系统可使海马回路中的特定神经元群失活，结果显示，失活的轴突在与活性轴突竞争后被消除。值得注意的是，在齿状回中，轴突精炼是通过成熟神经元和新生神经元之间的竞争来实现的，而齿状回在整个生命过程中都经历着神经发生。这些结果表明，活动依赖性竞争在体内功能性记忆回路的建立中发挥了多种作用。
