Impairment of retention but not acquisition of a visuomotor skill through time-dependent disruption of primary motor cortex
Impairment of retention but not acquisition of a visuomotor skill through time-dependent disruption of primary motor cortex
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DOI：
10.1523/jneurosci.2570-07.2007
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发表时间：
2007-12-05
影响因子：
5.3
通讯作者：
Shadmehr, Reza
中科院分区：
文献类型：
--
作者：
Hadipour-Niktarash, Arash;Lee, Christine K.;Shadmehr, Reza
学习视觉运动技能涉及到一个分布式网络，其中包括初级运动皮质(M1)。尽管有多种证据支持M1在运动学习和记忆中的作用，但目前还不清楚M1在学习的不同方面是否扮演着不同的角色，如习得和保持。在这里，我们通过使用单脉冲经颅磁刺激(TMS)对M1活动的时间特异性干扰来研究这一过程的性质和计时学。在快速手臂运动(类似于150ms持续时间)适应视觉运动旋转的过程中，我们将单脉冲TMS应用于M1或背侧运动前皮质(PMD)。当在每个试验结束后立即刺激M1或延迟700ms时，受试者表现出正常的适应能力。然而，尽管接受延迟TMS的受试者在去适应期间的记忆显示出正常的遗忘速度，但那些立即接受TMS的受试者的记忆更脆弱：在去适应期间，他们表现出更快的遗忘速度。以调整(降低)强度刺激PMD以排除M1刺激电流扩散引起的该结构共激活的可能性并不影响适应或保持。这些数据表明，在检测到运动错误后的短时间内，M1的神经加工在运动记忆的形成中起着至关重要的作用。M1中的这种加工可能代表了运动记忆的一个缓慢成分，它在保持过程中起着重要作用。
Learning a visuomotor skill involves a distributed network which includes the primary motor cortex (M1). Despite multiple lines of evidence supporting the role of M1 in motor learning and memory, it is unclear whether M1 plays distinct roles in different aspects of learning such as acquisition and retention. Here, we investigated the nature and chronometry of that processing through a temporally specific disruption of M1 activity using single-pulse transcranial magnetic stimulation (TMS). We applied single-pulse TMS to M1 or dorsal premotor cortex (PMd) during adaptation of rapid arm movements (similar to 150 ms duration) to a visuomotor rotation. When M1 was stimulated either immediately after the end of each trial or with a 700 ms delay, subjects exhibited normal adaptation. However, whereas the memory of the subjects who received delayed-TMS showed normal rates of forgetting during deadaptation, the memory of those who received immediate TMS was more fragile: in the deadaptation period, they showed a faster rate of forgetting. Stimulation of PMd with adjusted (reduced) intensity to rule out the possibility of coactivation of this structure caused by the current spread from M1 stimulation did not affect adaptation or retention. The data suggest that, during the short time window after detection of movement errors, neural processing in M1 plays a crucial role in formation of motor memories. This processing in M1 may represent a slow component of motor memory which plays a significant role in retention.