Surround inhibition is modulated by task difficulty
Surround inhibition is modulated by task difficulty
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DOI：
10.1016/j.clinph.2009.09.010
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发表时间：
2010-01-01
影响因子：
4.7
通讯作者：
Hallett, M.
中科院分区：
文献类型：
--
作者：
Beck, S.;Hallett, M.
目的：本研究的目的是通过比较简单反应时间任务 (SRT) 和选择反应时间任务 (CRT) 中的周围抑制 (SI) 的强度和时间进程，进一步表征初级运动皮层 (M1) 中的周围抑制 (SI)。方法：在 SRT 和 CRT 中，受试者对声信号做出相同的右手食指弯曲动作。对于 CRT，替代选择是使用左手食指进行类似的动作，但区别在于不同的音调。在这两项任务中，均在休息时、肌电图开始前 75 毫秒 (T1) 和 25 毫秒 (T2) 以及右侧第一背侧骨间肌 (FDI) 肌电图第一个峰值 (T3) 期间应用单脉冲经颅磁刺激 (TMS)。运动诱发电位 (MEP) 是从两个 FDI（在任务中充当协同剂）和右侧周围放松的拇短展肌 (APB) 记录的。结果：对于右手运动，与 SRT 相比，CRT 的 SI 开始得更早，并且更明显。对于 CRT 中的左手运动，SI 与右手运动相似。结论：我们得出结论，随着任务难度的增加，SI 发生得更早且更强。意义：抑制的时间和双侧效应表明，参与运动规划的运动区域（靠近运动皮层）有助于周围抑制的发生。由 Elsevier Ltd. 代表国际临床神经生理学联合会出版。
Objective: The aim of this study was to further characterize surround inhibition (SI) in the primary motor cortex (M1) by comparing its magnitude and time course during a simple reaction time task (SRT) and a choice reaction time task (CRT).Methods: In both the SRT and the CRT, subjects performed the same right index finger flexion in response to an acoustic signal. For CRT, the alternative choice was a similar movement using the left index finger, as distinguished by a different tone. In both tasks, single pulse transcranial magnetic stimulation (TMS) was applied at rest, 75 ms (T1) and 25 ms before EMG onset (T2), and during the first peak of EMG (T3) in the right first dorsal interosseous muscle (FDI). Motor evoked potentials (MEPs) were recorded from both FDIs, which act as synergists in the task, and the right surrounding, relaxed abductor pollicis brevis muscle (APB).Results: For right hand movement, SI started earlier and was more pronounced for CRT compared to SRT. For left hand movement in the CRT, SI was similar to that of right hand movement.Conclusions: We conclude that SI occurs earlier and stronger with increasing task difficulty.Significance: The timing as well as the bilateral effect of the inhibition suggests that motor areas involved in motor planning, proximate to the motor cortex, contribute to the genesis of surround inhibition. Published by Elsevier Ltd. on behalf of International Federation of Clinical Neurophysiology.