Rioult-Pedotti M S, Friedman D, Hess G, Donoghue J P
Department of Neuroscience, Brown University, Providence, Rhode Island 02912, USA.
Nat Neurosci. 1998 Jul;1(3):230-4. doi: 10.1038/678.
Learning a new motor skill requires an alteration in the spatiotemporal pattern of muscle activation. Motor areas of cerebral neocortex are thought to be involved in this type of learning, possibly by functional reorganization of cortical connections. Here we show that skill learning is accompanied by changes in the strength of connections within adult rat primary motor cortex (M1). Rats were trained for three or five days in a skilled reaching task with one forelimb, after which slices of motor cortex were examined to determine the effect of training on the strength of horizontal intracortical connections in layer II/III. The amplitude of field potentials in the forelimb region contralateral to the trained limb was significantly increased relative to the opposite 'untrained' hemisphere. No differences were seen in the hindlimb region. Moreover, the amount of long-term potentiation (LTP) that could be induced in trained M1 was less than in controls, suggesting that the effect of training was at least partly due to LTP-like mechanisms. These data represent the first direct evidence that plasticity of intracortical connections is associated with learning a new motor skill.
学习一项新的运动技能需要改变肌肉激活的时空模式。大脑新皮层的运动区域被认为参与了这类学习，可能是通过皮层连接的功能重组。在这里，我们表明技能学习伴随着成年大鼠初级运动皮层（M1）内连接强度的变化。大鼠用一个前肢进行了为期三天或五天的熟练抓握任务训练，之后检查运动皮层切片，以确定训练对II/III层水平皮质内连接强度的影响。相对于对侧“未训练”的半球，训练肢体对侧前肢区域的场电位幅度显著增加。在后肢区域未观察到差异。此外，在训练后的M1中可诱导的长时程增强（LTP）量少于对照组，这表明训练的效果至少部分归因于类似LTP的机制。这些数据代表了皮质内连接可塑性与学习新运动技能相关的首个直接证据。
