Left dorsal premotor cortex and supramarginal gyrus complement each other during rapid action reprogramming.
Left dorsal premotor cortex and supramarginal gyrus complement each other during rapid action reprogramming.
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在快速动作重编程过程中，左背前皮层和上环相互补充。
DOI：
10.1523/jneurosci.1010-12.2012
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发表时间：
2012-11-14
期刊：
影响因子：
--
通讯作者：
Siebner HR
中科院分区：
文献类型：
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作者：
Hartwigsen G;Bestmann S;Ward NS;Woerbel S;Mastroeni C;Granert O;Siebner HR
在面对突如其来的环境变化时，放弃已准备好的行动计划以支持替代行动的能力至关重要。我们测试了在动作重编程过程中，左侧边缘上回(SMG)的功能贡献是否取决于左侧背侧运动前皮质(PMD)的功能完整性。采用双部位重复经颅磁刺激(RTMS)策略，我们首先用离线的1赫兹rTMS瞬时干扰PMD，然后对SMG进行焦点“在线”rTMS，同时受试者执行空间预先设定的反应时间任务。SMG的有效在线RTMS而不是SMG的虚假RTMS在被试不得不重新编程他们的动作以响应无效的PRESS时增加了错误，而不管先前的离线RTMS的类型如何。这表明，Left SMG主要通过抑制无效准备的反应来促进行动的在线更新。在无效预先试验中，SMG的在线rTMS额外增加了正确反应的反应时间，但仅在PMD的离线rTMS之后。我们推测，离线rTMS导致PMD的额外功能障碍，这增加了SMG快速激活正确反应的功能相关性，并使SMG对在线rTMS的破坏性影响敏感。这些结果不仅提供了左PMD和SMG共同促进行动重新编程的因果证据，而且还表明这些区域各自的功能权重可以迅速重新分配。这一机制可能构成了功能网络的一个通用特征，允许对局灶性功能障碍做出快速功能补偿。
The ability to discard a prepared action plan in favor of an alternative action is critical when facing sudden environmental changes. We tested whether the functional contribution of left supramarginal gyrus (SMG) during action reprogramming depends on the functional integrity of left dorsal premotor cortex (PMd). Adopting a dual-site repetitive transcranial magnetic stimulation (rTMS) strategy, we first transiently disrupted PMd with “offline” 1Hz rTMS and then applied focal “online” rTMS to SMG whilst human subjects performed a spatially-precued reaction time task. Effective online rTMS of SMG but not sham rTMS of SMG increased errors when subjects had to reprogram their action in response to an invalid precue regardless of the type of preceding offline rTMS. This suggests that left SMG primarily contributes to the online updating of actions by suppressing invalidly prepared responses. Online rTMS of SMG additionally increased reaction times for correct responses in invalidly-precued trials, but only after offline rTMS of PMd. We infer that offline rTMS caused an additional dysfunction of PMd which increased the functional relevance of SMG for rapid activation of the correct response, and sensitized SMG to the disruptive effects of online rTMS. These results not only provide causal evidence that left PMd and SMG jointly contribute to action reprogramming, but also that the respective functional weight of these areas can be rapidly redistributed. This mechanism might constitute a generic feature of functional networks that allows for rapid functional compensation in response to focal dysfunctions.