Molecular Neurobiology Program, The Helen and Martin Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016, USA.
Nature. 2009 Dec 17;462(7275):920-4. doi: 10.1038/nature08577. Epub 2009 Nov 29.
Changes in synaptic connections are considered essential for learning and memory formation. However, it is unknown how neural circuits undergo continuous synaptic changes during learning while maintaining lifelong memories. Here we show, by following postsynaptic dendritic spines over time in the mouse cortex, that learning and novel sensory experience lead to spine formation and elimination by a protracted process. The extent of spine remodelling correlates with behavioural improvement after learning, suggesting a crucial role of synaptic structural plasticity in memory formation. Importantly, a small fraction of new spines induced by novel experience, together with most spines formed early during development and surviving experience-dependent elimination, are preserved and provide a structural basis for memory retention throughout the entire life of an animal. These studies indicate that learning and daily sensory experience leave minute but permanent marks on cortical connections and suggest that lifelong memories are stored in largely stably connected synaptic networks.
突触连接的变化被认为是学习和记忆形成的关键。然而，尚不清楚在学习过程中，神经回路如何在持续进行突触变化的同时保持终身记忆。在这里，我们通过在小鼠大脑皮层中随时间追踪突触后树突棘，发现学习和新的感官体验会通过一个延长的过程导致棘突的形成和消除。棘突重塑的程度与学习后的行为改善相关，这表明突触结构可塑性在记忆形成中起着关键作用。重要的是，由新体验诱导的一小部分新棘突，以及在发育早期形成并在经验依赖性消除中存活下来的大多数棘突，会被保留下来，并为动物整个生命周期的记忆保留提供结构基础。这些研究表明，学习和日常感官体验会在皮质连接上留下微小但持久的痕迹，并表明终身记忆储存在很大程度上稳定连接的突触网络中。
