Department of Psychology, University of Western Ontario, London, ON, N6A-5C2, Canada.
Exp Brain Res. 2010 Mar;201(3):411-9. doi: 10.1007/s00221-009-2050-8. Epub 2009 Oct 23.
It is far more difficult to detect a small tactile stimulation on a finger that is moving compared to when it is static. This suppression of tactile information during motion, known as tactile gating, has been examined in some detail during single-joint movements. However, the existence and time course of this gating has yet to be examined during visually guided multi-joint reaches, where sensory feedback may be paramount. The current study demonstrated that neurologically intact humans are unable to detect a small vibratory stimulus on one of their index fingers during a bimanual reach toward visual targets. By parametrically altering the delay between the visual target onset and the vibration, it was demonstrated that this gating was even apparent before participants started moving. A follow up experiment using electromyography indicated that gating was likely to occur even before muscle activity had taken place. This unique demonstration of tactile gating during a task reliant on visual feedback supports the notion this phenomenon is due to a central command, rather than a masking of sensory signals by afferent processing during movement.
与手指静止时相比，移动的手指上的小触觉刺激更难被察觉。这种在运动过程中对触觉信息的抑制，称为触觉门控，在单关节运动中已经被详细研究过。然而，在视觉引导的多关节伸展过程中，这种门控的存在和时间进程尚未被检测到，因为在这种情况下感觉反馈可能是最重要的。本研究表明，神经健全的人类在向视觉目标进行双手伸展时，无法察觉到其食指上的一个小振动刺激。通过参数化改变视觉目标出现和振动之间的延迟，可以证明这种门控甚至在参与者开始移动之前就已经很明显了。使用肌电图进行的后续实验表明，即使在肌肉活动发生之前，门控也可能发生。在依赖视觉反馈的任务中对手触觉门控的这种独特演示支持这样一种观点，即这种现象是由于中央命令引起的，而不是由于运动过程中感觉信号被传入处理所掩盖。
