The communication between dorsal premotor cortex (PMd) and primary motor cortex (M1) is important for visuomotor adaptation, but it is unclear how this relationship changes with advancing age. The present study recruited 21 young and 23 older participants for two experimental sessions during which intermittent theta burst stimulation (iTBS) or sham was applied over PMd. We assessed the effects of PMd iTBS on M1 excitability using motor evoked potentials (MEP) recorded from right first dorsal interosseous when single-pulse transcranial magnetic stimulation (TMS) was applied with posterior-anterior (PA) or anterior-posterior (AP) currents; and adaptation by quantifying error recorded during a visuomotor adaptation task (VAT). PMd iTBS potentiated PA ( < 0.0001) and AP ( < 0.0001) MEP amplitude in both young and older adults. PMd iTBS increased error in young adults during adaptation ( = 0.026), but had no effect in older adults ( = 0.388). Although PMd iTBS potentiated M1 excitability in both young and older adults, the intervention attenuated visuomotor adaptation specifically in young adults.

中文翻译：

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背侧前运动皮层的调节对年轻人和老年人的视觉运动适应有不同的影响


背侧前运动皮层 (PMd) 和初级运动皮层 (M1) 之间的通讯对于视觉运动适应很重要，但目前尚不清楚这种关系如何随着年龄的增长而变化。本研究招募了 21 名年轻参与者和 23 名老年参与者进行两次实验，期间在 PMd 上应用间歇性 theta 爆发刺激 (iTBS) 或假手术。当单脉冲经颅磁刺激 (TMS) 与后前 (PA) 或前-后 (AP) 电流一起应用时，我们使用从右第一背侧骨间记录的运动诱发电位 (MEP) 评估 PMd iTBS 对 M1 兴奋性的影响;通过量化视觉运动适应任务（VAT）期间记录的误差来进行适应。 PMd iTBS 增强了年轻人和老年人的 PA ( < 0.0001) 和 AP ( < 0.0001) MEP 幅度。 PMd iTBS 增加了年轻人适应过程中的误差 (= 0.026)，但对老年人没有影响 (= 0.388)。尽管 PMd iTBS 增强了年轻人和老年人的 M1 兴奋性，但干预措施尤其削弱了年轻人的视觉运动适应。