Stimulation-Induced Within-Representation and Across-Representation Plasticity in Human Motor Cortex
Stimulation-Induced Within-Representation and Across-Representation Plasticity in Human Motor Cortex
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DOI：
10.1523/jneurosci.22-13-05563.2002
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发表时间：
2002-07
期刊：
影响因子：
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通讯作者：
U. Ziemann;G. Wittenberg;L. Cohen
中科院分区：
文献类型：
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作者：
U. Ziemann;G. Wittenberg;L. Cohen
人类运动皮层包含一个动态的分布式运动表征网络。这些表示的形成、维护和修改是一个活动驱动的过程。重复刺激一个表征会导致该表征的运动输出增加，这一过程被称为“表征内可塑性”。我们先前表明，在对侧手的短暂性缺血性神经阻滞（INB）期间，重复经颅磁刺激（rTMS）被传递到该代表时，上臂代表的内代表可塑性发生。INB减少了运动皮层的抑制，从而降低了刺激诱导的可塑性阈值。在这里，我们研究了rTMS传递到附近的身体部位表示从上臂表示的电机输出的影响。6例健康受试者接受了INB单独治疗（对照）或INB加30分钟的面部、手部、手臂、腿部或运动皮层中重叠手臂/手部表征的局灶性0.1 Hz rTMS。INB单独给药和腿部代表的rTMS仅导致代表内短暂（60分钟）增加。相反，面部或手部表征的rTMS取消了短暂的增加，甚至导致手臂表征的运动输出的长期减少。因此，rTMS的实验去抑制运动皮层诱导内代表性的增加，和跨代表性的减少运动皮层输出。这种双向可塑性可能用于有目的地调节人类皮层功能。
The human motor cortex contains a dynamic and distributed network of motor representations. Formation, maintenance, and modification of these representations is an activity-driven process. Repeated stimulation of one representation results in increased motor output from this representation, a process referred to as “within-representation plasticity.” We showed previously that within-representation plasticity of the upper arm representation occurs when repetitive transcranial magnetic stimulation (rTMS) is delivered to that representation during transient ischemic nerve block (INB) of the contralateral hand. INB reduces inhibition in the motor cortex and thus lowers the threshold for stimulation-induced plasticity. Here we studied the effects of rTMS delivered to nearby body part representations on the motor output from the upper arm representation. Six healthy subjects underwent INB-alone (control), or INB plus 30 min of focal 0.1 Hz rTMS of either the face, hand, arm, leg, or overlap arm/hand representations in motor cortex. INB-alone and rTMS of the leg representation resulted in only a short-lasting ( 60 min) within-representation increase. In contrast, rTMS of face or hand representations canceled the short-lasting increase and even led to a long-lasting decrease of motor output from the arm representation. Therefore, rTMS of the experimentally disinhibited motor cortex induces within-representation increase, and across-representation decrease of motor cortical output. This bidirectional plasticity might be used for purposeful modulation of human cortical function.