Modulation of interhemispheric interactions across symmetric and asymmetric bimanual force regulations
Modulation of interhemispheric interactions across symmetric and asymmetric bimanual force regulations
复制标题
跨对称和不对称双手力调节的半球间相互作用的调节
DOI：
10.1111/ejn.12026
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发表时间：
2013
影响因子：
3.4
通讯作者：
Komiyama T
中科院分区：
文献类型：
--
作者：
Tazoe T;Sasada S;Sakamoto M;Komiyama T
胼胝体对于左右半球之间的神经交流至关重要。虽然双手动作的时空协调是由跨胼胝体神经回路的活动介导的，但跨胼胝体神经活动如何参与人类双手力量执行的动态控制仍有待解决。为了解决这个问题，我们研究了单脉冲经颅磁刺激（TMS）引起的经胼胝体抑制（TCI）与双手力调节的协调条件。在视觉引导双手力跟踪任务中，两个拇指同相（对称条件）或异相180°（不对称条件）外展。将TMS施加于左侧初级运动皮层，以引起TCI引起的同侧左侧力追踪障碍。两种情况下的跟踪精度相当，但对称情况下左右跟踪轨迹的同步性高于非对称情况。对称条件下的力扰动和TCI的大小大于非对称条件下。右手单手力追踪既不影响力干扰，也不影响TCI在紧张性左手拇指外展。此外，这些TMS诱导的同侧运动障碍仅在TMS强度足以激发经胼胝体回路时出现，而不管交叉皮质脊髓束是否被激活。这些研究结果支持的假设，大脑半球之间的相互作用的运动皮层发挥了重要作用，在调制双手力量协调任务，TCI微调取决于双手力量调节的协调条件。
The corpus callosum is essential for neural communication between the left and right hemispheres. Although spatiotemporal coordination of bimanual movements is mediated by the activity of the transcallosal circuit, it remains to be addressed how transcallosal neural activity is involved in the dynamic control of bimanual force execution in human. To address this issue, we investigated transcallosal inhibition (TCI) elicited by single‐pulse transcranial magnetic stimulation (TMS) in association with the coordination condition of bimanual force regulation. During a visually‐guided bimanual force tracking task, both thumbs were abducted either in‐phase (symmetric condition) or 180° out‐of‐phase (asymmetric condition). TMS was applied to the left primary motor cortex to elicit the disturbance of ipsilateral left force tracking due to TCI. The tracking accuracy was equivalent between the two conditions, but the synchrony of the left and right tracking trajectories was higher in the symmetric condition than in the asymmetric condition. The magnitude of force disturbance and TCI were larger during the symmetric condition than during the asymmetric condition. Right unimanual force tracking influenced neither the force disturbance nor TCI during tonic left thumb abduction. Additionally, these TMS‐induced ipsilateral motor disturbances only appeared when the TMS intensity was strong enough to excite the transcallosal circuit, irrespective of whether the crossed corticospinal tract was activated. These findings support the hypotheses that interhemispheric interactions between the motor cortices play an important role in modulating bimanual force coordination tasks, and that TCI is finely tuned depending on the coordination condition of bimanual force regulation.