Hemispheric differences in use-dependent corticomotor plasticity in young and old adults
Hemispheric differences in use-dependent corticomotor plasticity in young and old adults
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DOI：
10.1007/s00221-010-2332-1
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发表时间：
2010-08-01
影响因子：
2
通讯作者：
Semmler, John G.
中科院分区：
文献类型：
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作者：
Cirillo, John;Rogasch, Nigel C.;Semmler, John G.
本研究的目的是检查年轻人和老年人的左手和右手重复拇指外展训练后皮质运动的兴奋性和可塑性。对 12 名年轻人（18-27 岁）和 14 名老年人（63-75 岁）的拇短展肌 (APB) 进行肌电图记录。运动训练包括 300 次拇指弹道外展，以最大限度地提高峰值外展加速度，每只手都在单独的训练中进行测试。使用初级运动皮层 (M1) 上的经颅磁刺激 (TMS) 来评估训练前后对侧 APB 运动诱发电位 (MEP) 和短间隔皮质内抑制 (SICI) 的变化。对于年轻人和老年人，训练后双手的 APB MEP 振幅增加，这表明使用依赖的可塑性。然而，与右手（惯用手）相比，左手（非惯用手）的 MEP 幅度增加了 21% (P = 0.04)。尽管与年轻受试者的左手 (P < 0.04) 和老年受试者的右手 (P < 0.01) 相比，年轻受试者的右手拇指外展峰值加速度（运动学习）提高了 40%，但还是出现了这种情况。此外，在年轻人和老年人之间没有观察到使用依赖性可塑性的差异，并且所有受试者在进行双手弹道训练后 SICI 保持不变。这些发现表明，在简单的拇指弹道训练中，与右手相比，控制左手的皮质运动回路得到了更大的加强，并且仅在惯用手中观察到与年龄相关的运动学习下降。与之前的研究相比，这些数据还表明，年轻人和老年人在这项简单的拇指训练任务中可以表现出类似的依赖于使用的皮质运动可塑性。
The aim of this study was to examine corticomotor excitability and plasticity following repetitive thumb abduction training in left and right hands of young and old adults. Electromyographic recordings were obtained from the abductor pollicis brevis (APB) muscle of 12 young (aged 18-27 years) and 14 old (aged 63-75 years) adults. Motor training consisted of 300 ballistic abductions of the thumb to maximize peak abduction acceleration, with each hand tested in a separate session. Transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) was used to assess changes in contralateral APB motor-evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) before and after training. For young and old adults, APB MEP amplitude increased for both hands after training, which is indicative of use-dependent plasticity. However, the increase in MEP amplitude was 21% (P = 0.04) greater in the left (non-dominant) hand compared with the right (dominant) hand. This occurred despite a 40% greater improvement in peak thumb abduction acceleration (motor learning) for the right hand in young subjects compared with the left hand in young subjects (P < 0.04) and the right hand in old subjects (P < 0.01). Furthermore, no difference in use-dependent plasticity was observed between young and old adults, and SICI remained unchanged following ballistic training for both hands in all subjects. These findings suggest that there is greater strengthening of corticomotor circuits for control of the left compared with the right hand during simple ballistic thumb training and that an age-related decline in motor learning was observed only in the dominant hand. In contrast to previous studies, these data also indicate that young and old adults can demonstrate similar use-dependent corticomotor plasticity during this simple thumb-training task.