Bonato C, Zanette G, Polo A, Bongiovanni G, Manganotti P, Tinazzi M, Teatini F, Fiaschi A
Dipartimento di Scienze Neurologiche e della Visione, Policlinico Borgo Roma, Verona, Italy.
Ital J Neurol Sci. 1994 Dec;15(9):489-94. doi: 10.1007/BF02334610.
Transcranial magnetic stimulation was used to evaluate changes in motor cortex excitability after rapid repetitive movements in five healthy subjects aged 23-30 years, by considering the amplitude of motor evoked potentials (MEPs) at rest and after one minute of maximal frequency repetitive abduction-adduction movements of the thumb. In addition, M and F waves were evaluated by stimulating the median nerve at the wrist. All of the examined subjects showed a clear modification in post-exercise MEP amplitudes, with a mean maximal reduction of 50-60% in comparison with basal values and complete recovery after a period of about 35 minutes. The time course of this phenomenon showed a triphasic pattern: (I) a rapid decrease phase up to the fifth minute; (II) a maximal depression phase for a period of about ten minutes; (III) a slow return to basal values. No significant changes were observed in post-exercise M and F waves. These results show the existence of a reversible modulation of the excitability of the upper motor neuron after rapid repetitive movements. It is likely that this modulation takes place at the level of the motor cortex and that its anatomo-functional substrate is represented by the activation of inhibitory intracortical circuits.
采用经颅磁刺激技术，通过测量5名年龄在23至30岁之间的健康受试者在静息状态下以及拇指进行一分钟最大频率重复外展-内收运动后的运动诱发电位（MEP）幅度，来评估快速重复运动后运动皮层兴奋性的变化。此外，通过刺激腕部正中神经来评估M波和F波。所有受试对象在运动后MEP幅度均出现明显变化，与基础值相比平均最大降低50%-60%，并在约35分钟后完全恢复。该现象的时间进程呈三相模式：（I）直至第5分钟的快速下降期；（II）约10分钟的最大抑制期；（III）缓慢恢复至基础值。运动后M波和F波未观察到显著变化。这些结果表明，快速重复运动后上运动神经元的兴奋性存在可逆性调节。这种调节可能发生在运动皮层水平，其解剖功能基础可能是抑制性皮质内回路的激活。
