Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, United States.
Krasnow Institute for Advanced Study, George Mason University, Fairfax, United States.
Elife. 2018 Oct 25;7:e38588. doi: 10.7554/eLife.38588.
Synaptic plasticity, which underlies learning and memory, depends on calcium elevation in neurons, but the precise relationship between calcium and spatiotemporal patterns of synaptic inputs is unclear. Here, we develop a biologically realistic computational model of striatal spiny projection neurons with sophisticated calcium dynamics, based on data from rodents of both sexes, to investigate how spatiotemporally clustered and distributed excitatory and inhibitory inputs affect spine calcium. We demonstrate that coordinated excitatory synaptic inputs evoke enhanced calcium elevation specific to stimulated spines, with lower but physiologically relevant calcium elevation in nearby non-stimulated spines. Results further show a novel and important function of inhibition-to enhance the difference in calcium between stimulated and non-stimulated spines. These findings suggest that spine calcium dynamics encode synaptic input patterns and may serve as a signal for both stimulus-specific potentiation and heterosynaptic depression, maintaining balanced activity in a dendritic branch while inducing pattern-specific plasticity.
突触可塑性是学习和记忆的基础，依赖于神经元中的钙升高，但钙与突触输入的时空模式之间的精确关系尚不清楚。在这里，我们基于来自雌雄两性啮齿动物的数据，开发了一种具有复杂钙动力学的纹状体棘突投射神经元的生物现实计算模型，以研究时空聚类和分布的兴奋性和抑制性输入如何影响棘突钙。我们证明，协调的兴奋性突触输入会引起特定于受刺激棘突的钙升高，而附近未受刺激的棘突中的钙升高较低，但具有生理相关性。结果进一步显示了抑制的一个新的和重要功能，即增强刺激和未刺激棘突之间的钙差异。这些发现表明，棘突钙动力学编码突触输入模式，并可能作为刺激特异性增强和异突触抑制的信号，在维持树突分支的平衡活动的同时，诱导特定模式的可塑性。
