Neuroplasticity underpins motor learning, with abnormal neuroplasticity related to age-associated motor declines. Bilateral transfer of motor learning, through rehabilitation, may mitigate these declines; however, the magnitude of transfer may be reduced in older populations. This study investigated excitatory and inhibitory pathways in the trained and untrained hemispheres following unilateral training of a complex finger-tapping task across ageing. Fifteen young (26.2 ± 3.8 years) and 11 older adults (63.7 ± 15.4 years) received transcranial magnetic stimulation, although surface electromyography was recorded from the extensor digitorum communis (EDC) and abductor pollicis brevis (APB), before and after practicing a complex finger-tapping task with the dominant hand. Excitability, inhibition (expressed as percent change scores from pre- to post-training), motor task performance and bilateral transfer were assessed between groups. Investigation of hemispheric differences within each group was completed for measures that significantly differed between groups. There were no between-group differences in task performance or bilateral transfer, with task performance improving post-training irrespective of group for both hands (p < 0.05). Pre- to post-inhibition change scores of the untrained EDC muscle increased (p = 0.034) in older compared with younger adults, indicating reduced inhibition in older adults. Inhibition change scores significantly differed between hemispheres for the young group only (p = 0.037). Only the younger group presented with hemispheric lateralisation, providing some support for the Hemispheric Asymmetry Reduction in OLDer adults (HAROLD) hypothesis. Whether this reduction is evidence of de-differentiation or compensation will need to be confirmed with additional measures.

中文翻译：

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年轻人和老年人单侧复杂手指敲击任务后的抑制、兴奋和双侧转移

神经可塑性是运动学习的基础，异常的神经可塑性与年龄相关的运动衰退有关。通过康复，运动学习的双边转移可能会减轻这些下降；然而，老年人口的转移程度可能会降低。本研究调查了受过训练和未经训练的大脑半球在单侧训练复杂的手指敲击任务后的兴奋和抑制途径。15 名年轻人 (26.2 ± 3.8 岁) 和 11 名老年人 (63.7 ± 15.4 岁) 接受了经颅磁刺激，尽管在练习复杂的前后伸肌 (EDC) 和拇短展肌 (APB) 记录了表面肌电图用惯用手进行手指敲击任务。兴奋性，抑制（表示为从训练前到训练后的百分比变化分数）、运动任务表现和组间转移。对于组间显着不同的测量，完成了每组内半球差异的调查。在任务表现或双边转移方面没有组间差异，无论双手在哪个组，训练后的任务表现都有改善（p  < 0.05)。 与年轻人相比，老年人未经训练的 EDC 肌肉的抑制前后变化评分增加 ( p = 0.034)，表明老年人的抑制减少。仅年轻组的半球之间的抑制变化评分显着不同（p  = 0.037）。只有较年轻的组出现半球偏侧化，为老年人半球不对称减少 (HAROLD) 假设提供了一些支持。这种减少是否是去分化或补偿的证据，需要通过额外的措施来确认。