Response learning stimulates dendritic spine growth on dorsal striatal medium spiny neurons
Response learning stimulates dendritic spine growth on dorsal striatal medium spiny neurons
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DOI：
10.1016/j.nlm.2018.06.008
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发表时间：
2018-11-01
影响因子：
2.7
通讯作者：
Gould, Elizabeth
中科院分区：
文献类型：
--
作者：
Briones, Brandy A.;Tang, Vincent D.;Gould, Elizabeth
树突棘（兴奋性突触部位）数量和/或大小的增加与不同类型的学习以及多个大脑区域（包括海马体、感觉皮层、运动皮层和小脑）的突触可塑性有关。相比之下，之前的一项研究报告称，需要背侧纹状体的迷宫任务训练对该区域的中型多刺神经元树突棘没有影响。这些发现可能表明大脑区域特定的可塑性水平差异以及不同类型学习背后的不同细胞过程。先前的研究没有调查树突棘密度的变化是否可能局限于中型多刺神经元的特定亚群，也没有检查接受背外侧纹状体依赖性迷宫任务训练的大鼠的树突棘与在没有训练的情况下暴露于相同类型迷宫的大鼠的树突棘进行比较。为了进一步解决这些问题，我们在训练组和未训练组中用亲脂性染料 DiI 标记中等多棘神经元，并对立即早期基因 zif 268（神经元激活的间接标记）的蛋白质产物进行染色。我们发现，经过短期强化训练后，背外侧纹状体的中等棘神经元的树突棘密度虽小但显着增加，并且蘑菇形态的棘密度大幅增加，而薄形态的棘密度则减少。然而，这些结果与 zif 268 表达无关。我们的研究结果表明，对背外侧纹状体依赖的迷宫任务进行短期强化训练会导致树突棘密度快速增加，以及背外侧纹状体中型多棘神经元的成熟，这种效应可能有助于在迷宫训练中早期获得习得反应。
Increases in the number and/or the size of dendritic spines, sites of excitatory synapses, have been linked to different types of learning as well as synaptic plasticity in several brain regions, including the hippocampus, sensory cortex, motor cortex, and cerebellum. By contrast, a previous study reported that training on a maze task requiring the dorsal striatum has no effect on medium spiny neuron dendritic spines in this area. These findings might suggest brain region-specific differences in levels of plasticity as well as different cellular processes underlying different types of learning. No previous studies have investigated whether dendritic spine density changes may be localized to specific subpopulations of medium spiny neurons, nor have they examined dendritic spines in rats trained on a dorsolateral striatum-dependent maze task in comparison to rats exposed to the same type of maze in the absence of training. To address these questions further, we labeled medium spiny neurons with the lipophilic dye DiI and stained for the protein product of immediate early gene zif 268, an indirect marker of neuronal activation, in both trained and untrained groups. We found a small but significant increase in dendritic spine density on medium spiny neurons of the dorsolateral striatum after short-term intensive training, along with robust increases in the density of spines with mushroom morphology coincident with reductions in the density of spines with thin morphology. However, these results were not associated with zif 268 expression. Our findings suggest that short-term intensive training on a dorsolateral striatum-dependent maze task induces rapid increases in dendritic spine density and maturation on medium spiny neurons of the dorsolateral striatum, an effect which may contribute to early acquisition of the learned response in maze training.