Structural dynamics and stability of corticocortical and thalamocortical axon terminals during motor learning
Structural dynamics and stability of corticocortical and thalamocortical axon terminals during motor learning
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DOI：
10.1371/journal.pone.0234930
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发表时间：
2020-06-19
期刊：
影响因子：
3.7
通讯作者：
Matsuzaki, Masanori
中科院分区：
文献类型：
--
作者：
Hasegawa, Ryota;Ebina, Teppei;Matsuzaki, Masanori
突触可塑性是学习和记忆的细胞基础。当动物学习一种新的运动技能时，在初级运动皮层（M1）中诱导突触修饰，并且在学习的早期形成与运动记忆相关的新的突触后树突棘。然而，它是知之甚少突触前轴突终扣的形成，消除，并在运动学习过程中保持，以及是否长距离皮质和丘脑皮质轴突终扣显示不同的结构变化在学习过程中。在这项研究中，我们进行了双光子成像的突触前终扣的长距离轴突在第1层（L1）的小鼠M1在7天的学习加速旋转杆任务。从次级运动皮质区投射的轴突上的终扣的训练期平均形成率增加，而从运动丘脑（丘脑终扣）的平均消除率下降。特别地，在第4-7天期间丘脑终扣的消除率低于未训练的小鼠，并且存活至第7天的预先存在的丘脑终扣的分数高于未训练的小鼠。我们的研究结果表明，在M1的丘脑终扣的后期稳定有助于运动技能的学习。
Synaptic plasticity is the cellular basis of learning and memory. When animals learn a novel motor skill, synaptic modifications are induced in the primary motor cortex (M1), and new postsynaptic dendritic spines relevant to motor memory are formed in the early stage of learning. However, it is poorly understood how presynaptic axonal boutons are formed, eliminated, and maintained during motor learning, and whether long-range corticocortical and thalamocortical axonal boutons show distinct structural changes during learning. In this study, we conducted two-photon imaging of presynaptic boutons of long-range axons in layer 1 (L1) of the mouse M1 during the 7-day learning of an accelerating rotarod task. The training-period-averaged rate of formation of boutons on axons projecting from the secondary motor cortical area increased, while the average rate of elimination of those from the motor thalamus (thalamic boutons) decreased. In particular, the elimination rate of thalamic boutons during days 4-7 was lower than that in untrained mice, and the fraction of pre-existing thalamic boutons that survived until day 7 was higher than that in untrained mice. Our results suggest that the late stabilization of thalamic boutons in M1 contributes to motor skill learning.