Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Cerebellum. 2018 Dec;17(6):756-765. doi: 10.1007/s12311-018-0963-0.
There are multiple types of plasticity at both excitatory glutamatergic and inhibitory GABAergic synapses onto a cerebellar Purkinje neuron (PN). At parallel fiber to PN synapses, long-term depression (LTD) and long-term potentiation (LTP) occur, while at molecular layer interneuron to PN synapses, a type of LTP called rebound potentiation (RP) takes place. LTD, LTP, and RP seem to contribute to motor learning. However, each type of synaptic plasticity might play a different role in various motor learning paradigms. In addition, defects in one type of synaptic plasticity could be compensated by other forms of synaptic plasticity, which might conceal the contribution of a particular type of synaptic plasticity to motor learning. The threshold stimulation for inducing each type of synaptic plasticity and the induction conditions are different for different plasticity mechanisms, and they change depending on the state of an animal. Facilitation and/or saturation of synaptic plasticity occur after certain behavioral experiences or in some transgenic mice. Thus, the regulation and roles of synaptic plasticity are complicated. Toward a comprehensive understanding of the respective roles of each type of synaptic plasticity and their possible interactions during motor learning processes, I summarize induction conditions, modulations, interactions, and saturation of synaptic plasticity and discuss how multiple types of synaptic plasticity in a PN might work together in motor learning processes.
小脑浦肯野神经元（PN）上的兴奋性谷氨酸能和抑制性 GABA 能突触都存在多种类型的可塑性。在平行纤维到 PN 突触上，会发生长时程抑制（LTD）和长时程增强（LTP），而在分子层中间神经元到 PN 突触上，则会发生一种称为反弹增强（RP）的 LTP。LTD、LTP 和 RP 似乎都有助于运动学习。然而，每种类型的突触可塑性在不同的运动学习范式中可能发挥不同的作用。此外，一种类型的突触可塑性缺陷可以被其他形式的突触可塑性所补偿，这可能掩盖了特定类型的突触可塑性对运动学习的贡献。诱导每种类型的突触可塑性的阈值刺激和诱导条件因不同的可塑性机制而异，并且它们会根据动物的状态而变化。在某些行为经验后或在某些转基因小鼠中，会发生突触可塑性的易化和/或饱和。因此，突触可塑性的调节和作用很复杂。为了全面了解每种类型的突触可塑性在运动学习过程中的各自作用及其可能的相互作用，我总结了突触可塑性的诱导条件、调节、相互作用和饱和，并讨论了 PN 中的多种类型的突触可塑性如何在运动学习过程中协同工作。
