Reorganization of Recurrent Layer 5 Corticospinal Networks Following Adult Motor Training
Reorganization of Recurrent Layer 5 Corticospinal Networks Following Adult Motor Training
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DOI：
10.1523/jneurosci.3442-17.2019
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发表时间：
2019-06-12
影响因子：
5.3
通讯作者：
Tuszynski, Mark H.
中科院分区：
文献类型：
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作者：
Biane, Jeremy S.;Takashima, Yoshio;Tuszynski, Mark H.
相邻神经元之间的递归突触连接是哺乳动物皮层的一个关键特征，占皮层输入的绝大多数。虽然计算模型表明，经常性连接的重组是经验依赖性皮层调谐的主要驱动因素，但经常性网络可塑性的真正生物学特征尚未得到很好的识别。事实上，皮层神经元之间的连接是否会像人们普遍预测的那样在行为训练中发生重新布线，仍然是未知数。在这里，我们探测成年雄性大鼠运动训练后的M1循环回路，并在功能相关的第5层神经元之间发现了强大的突触重组，导致循环连接概率增加2.5倍。这种重组是特定的神经元亚群最相关的执行训练的运动技能，行为表现受损后，有针对性的分子抑制这个亚群。相比之下，相邻的第5层神经元之间的递归连接不受影响，这与训练的行为基本无关。训练相关的皮质脊髓细胞在训练后也表现出增加的兴奋性。这些研究结果建立了训练后成年期复发性皮层网络的选择性修改。
Recurrent synaptic connections between neighboring neurons are a key feature of mammalian cortex, accounting for the vast majority of cortical inputs. Although computational models indicate that reorganization of recurrent connectivity is a primary driver of experiencedependent cortical tuning, the true biological features of recurrent network plasticity are not well identified. Indeed, whether rewiring of connections between cortical neurons occurs during behavioral training, as is widely predicted, remains unknown. Here, we probe M1 recurrent circuits following motor training in adult male rats and find robust synaptic reorganization among functionally related layer 5 neurons, resulting in a 2.5-fold increase in recurrent connection probability. This reorganization is specific to the neuronal subpopulation most relevant for executing the trained motor skill, and behavioral performance was impaired following targeted molecular inhibition of this subpopulation. In contrast, recurrent connectivity is unaffected among neighboring layer 5 neurons largely unrelated to the trained behavior. Training-related corticospinal cells also express increased excitability following training. These findings establish the presence of selective modifications in recurrent cortical networks in adulthood following training.