Abstract：
Integration of new neurons into adult hippocampal circuits is a process coordinated by local and long-range synaptic inputs. To achieve stable integration and uniquely contribute to hippocampal function, immature neurons are endowed with a critical period of heightened synaptic plasticity, yet it remains unclear which mechanisms sustain this form of plasticity during neuronal maturation. We found that as new neurons enter their critical period, a transient surge in fusion dynamics stabilizes elongated mitochondrial morphologies in dendrites to fuel synaptic plasticity. Conditional ablation of fusion dynamics to prevent mitochondrial elongation selectively impaired spine plasticity and synaptic potentiation, disrupting neuronal competition for stable circuit integration, ultimately leading to decreased survival. Despite profuse mitochondrial fragmentation, manipulation of competition dynamics was sufficient to restore neuronal survival but left neurons poorly responsive to experience at the circuit level. Thus, by enabling synaptic plasticity during the critical period, mitochondrial fusion facilitates circuit remodeling by adult-born neurons.
摘要：
将新神经元整合到成年海马回路是由局部和远程突触输入协调的过程。为了实现稳定的整合并独特地促进海马功能，未成熟的神经元被赋予了突触可塑性增强的关键时期，然而，目前尚不清楚哪些机制在神经元成熟过程中维持这种形式的可塑性。我们发现，随着新的神经元进入他们的关键时期，融合动力学的短暂激增稳定了树突中细长的线粒体形态，以促进突触可塑性。条件性消融融合动力学以防止线粒体伸长选择性受损的脊柱可塑性和突触增强，破坏神经元竞争以获得稳定的电路集成，最终导致生存率下降。尽管大量的线粒体片段化，操纵竞争动力学足以恢复神经元的存活，但使神经元对电路水平的经验反应不佳。因此，通过在关键时期实现突触可塑性，线粒体融合促进成年神经元的回路重塑。
