Plasticity of motor threshold and motor-evoked potential amplitude - A model of intrinsic and synaptic plasticity in human motor cortex?
Plasticity of motor threshold and motor-evoked potential amplitude - A model of intrinsic and synaptic plasticity in human motor cortex?
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DOI：
10.1016/j.brs.2011.11.005
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发表时间：
2012-10-01
影响因子：
7.7
通讯作者：
Mall, Volker
中科院分区：
文献类型：
--
作者：
Delvendahl, Igor;Jung, Nikolai H.;Mall, Volker
背景：神经元可塑性是学习记忆的生理基础。在动物实验中，突触（即长时程增强（LTP）和抑制（LTD））和内在可塑性是不同的。在人类运动皮质中，皮质可塑性可以使用经颅磁刺激（TMS）来证明。运动诱发电位（motor-evoked potential，MEP）幅度的变化最可能代表突触可塑性，因此被称为LTP样和LTD样plasticity.Objective/hypothesis：我们研究了运动阈值变化的作用及其与MEP幅度变化的关系。采用刺激间隔为25 ms或10 ms的配对联想刺激（PAS）或运动训练（MP）诱导脑可塑性结果：观察到PAS[25]、PAS[10]和MP后MEP波幅和运动阈值的变化。在所有三种方案中，MEP振幅的长期个体变化与运动阈值的变化呈负相关（PAS[25]：P = .003，n = 36; PAS[10]：P = .038，n = 19; MP：P = .041，n = 19）。而MEP幅度的增加和减少被认为代表运动皮层输出神经元的LTP样或LTD样突触可塑性，MT的变化可以被认为是内在可塑性的相关性。(C)2012 Elsevier Inc. All rights reserved.
Background: Neuronal plasticity is the physiological correlate of learning and memory. In animal experiments, synaptic (i.e. long-term potentiation (LTP) and depression (LTD)) and intrinsic plasticity are distinguished. In human motor cortex, cortical plasticity can be demonstrated using transcranial magnetic stimulation (TMS). Changes in motor-evoked potential (MEP) amplitudes most likely represent synaptic plasticity and are thus termed LTP-like and LTD-like plasticity.Objective/hypothesis: We investigated the role of changes of motor threshold and their relation to changes of MEP amplitudes.Methods: We induced plasticity by paired associative stimulation (PAS) with 25 ms or 10 ms inter-stimulus interval or by motor practice (MP) in 64 healthy subjects aged 18-31 years (median 24.0).Results: We observed changes of MEP amplitudes and motor threshold after PAS[25], PAS[10] and MP. In all three protocols, long-term individual changes in MEP amplitude were inversely correlated to changes in motor threshold (PAS[25]: P = .003, n = 36; PAS[10]: P = .038, n = 19; MP: P = .041, n = 19).Conclusion: We conclude that changes of MEP amplitudes and MT represent two indices of motor cortex plasticity. Whereas increases and decreases in MEP amplitude are assumed to represent LTP-like or LTD-like synaptic plasticity of motor cortex output neurons, changes of MT may be considered as a correlate of intrinsic plasticity. (C) 2012 Elsevier Inc. All rights reserved.