Mapping the dynamics of cortical neuroplasticity of skilled motor learning using micro X-ray fluorescence and histofluorescence imaging of zinc in the rat.
Mapping the dynamics of cortical neuroplasticity of skilled motor learning using micro X-ray fluorescence and histofluorescence imaging of zinc in the rat.
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DOI：
10.1016/j.bbr.2016.11.002
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发表时间：
2017-02-01
影响因子：
2.7
通讯作者：
Paterson PG
中科院分区：
文献类型：
--
作者：
Alaverdashvili M;Paterson PG
最近已实施了锌（Zn）的基于同步加速器的X射线荧光成像（XFI），以了解针对中风后神经保护和神经可塑性的各种治疗干预的效率。然而，目前尚不确定微XFI是否可以解决神经可塑性引起的变化。因此，我们探讨了学习相关的行为变化是否伴随着健康成年大鼠大脑皮层锌浓度的变化。在运动学习的早期和晚期阶段，熟练的伸手去吃任务的熟练程度是神经可塑性的一个功能指标。采用c-Fos蛋白和囊泡锌表达作为脑可塑性的间接神经元测量。微XFI生成的总锌图（20 × 20 × 30 μ m3分辨率）未能反映训练前肢对侧运动皮层中c-Fos或囊泡锌的增加或熟练伸手任务的熟练程度提高。值得注意的是，囊泡锌增加，在运动学习的后期沿着与c-fos-ip神经元的数量减少相对于运动学习的早期阶段。随着运动技能的进步，c-fos和囊泡锌水平的这种逆动力学表明，由更少的活跃但更有效地连接的神经元组成的质的不同的神经群体支持在运动学习的晚期与早期阶段的熟练动作。缺乏敏感性的XFI生成的锌地图可视化的可塑性相关的变化，泡状锌表明，锌水平测量微XFI不应被用作替代标记的神经可塑性，在收购熟练的运动动作。纳米XFI可以在未来探索作为成像这些微妙的生理变化的手段。
Synchrotron-based X-ray fluorescence imaging (XFI) of zinc (Zn) has been recently implemented to understand the efficiency of various therapeutic interventions targeting post-stroke neuroprotection and neuroplasticity. However, it is uncertain if micro XFI can resolve neuroplasticity-induced changes. Thus, we explored if learning-associated behavioral changes would be accompanied by changes in cortical Zn concentration measured by XFI in healthy adult rats. Proficiency in a skilled reach-to-eat task during early and late stages of motor learning served as a functional measure of neuroplasticity. c-Fos protein and vesicular Zn expression were employed as indirect neuronal measures of brain plasticity. A total Zn map (20 × 20 × 30 μm3 resolution) generated by micro XFI failed to reflect increases in either c-Fos or vesicular Zn in the motor cortex contralateral to the trained forelimb or improved proficiency in the skilled reaching task. Remarkably, vesicular Zn increased in the late stage of motor learning along with a concurrent decrease in the number of c-fos-ip neurons relative to the early stage of motor learning. This inverse dynamics of c-fos and vesicular Zn level as the motor skill advances suggest that a qualitatively different neural population, comprised of fewer active but more efficiently connected neurons, supports a skilled action in the late versus early stage of motor learning. The lack of sensitivity of the XFI-generated Zn map to visualize the plasticity-associated changes in vesicular Zn suggests that the Zn level measured by micro XFI should not be used as a surrogate marker of neuroplasticity in response to the acquisition of skilled motor actions. Nanoscopic XFI could be explored in future as a means of imaging these subtle physiological changes.