In excitatory neurons, most glutamatergic synapses are made on the heads of dendritic spines, each of which houses the postsynaptic terminal of a single glutamatergic synapse. We review recent studies demonstrating in vivo that spines are motile and plastic structures whose morphology and lifespan are influenced, even in adult animals, by changes in sensory input. However, most spines that appear in adult animals are transient, and the addition of stable spines and synapses is rare. In vitro studies have shown that patterns of neuronal activity known to induce synaptic plasticity can also trigger changes in spine morphology. Therefore, it is tempting to speculate that the plastic changes of spine morphology reflect the dynamic state of its associated synapse and are responsible to some extent for neuronal circuitry remodeling. Nevertheless, morphological changes are not required for all forms of synaptic plasticity, and whether changes in the spine shape and size significantly impact synaptic signals is unclear.

中文翻译：

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树突棘的解剖和生理可塑性。

在兴奋性神经元中，大多数谷氨酸能突触发生在树突棘的头部，每个突突都容纳单个谷氨酸能突触的突触后末端。我们回顾了最近的研究，这些研究表明在体内，刺是活动的和可塑的结构，即使在成年动物中，其形态和寿命也会受到感觉输入变化的影响。但是，成年动物中出现的大多数棘是短暂的，并且很少添加稳定的棘和突触。体外研究表明，已知可诱导突触可塑性的神经元活动模式也可触发脊柱形态变化。因此，很容易推测脊柱形态的塑性变化反映了其相关突触的动态状态，并在一定程度上对神经元回路的重建负责。不过，