Transcranial magnetic stimulation of the human frontal eye field: Effects on visual perception and attention
Transcranial magnetic stimulation of the human frontal eye field: Effects on visual perception and attention
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DOI：
10.1162/089892902320474553
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发表时间：
2002-10-01
影响因子：
3.2
通讯作者：
Paus, T
中科院分区：
文献类型：
--
作者：
Grosbras, MH;Paus, T
当观看一个物体时，人类受试者可以将注意力转移到视野中的另一个物体上，而无需移动眼睛。这种注意力的转移会激活与执行眼球运动相同的大脑区域。在这里，我们研究主要皮质动眼区域之一，即额叶视野（FEF）在注意力转移中的作用。我们使用了经颅磁刺激（TMS），这是一种已知会破坏短暂眼球运动准备的技术。我们假设，如果 FEF 是涉及在不移动眼睛的情况下转移注意力的网络中的必要元素，那么 TMS 也应该会扰乱视觉空间注意力。对于每个志愿者，我们将 TMS 线圈放置在 FEF 的概率解剖位置上，并验证单脉冲会延迟眼球运动。然后我们在视觉空间注意力任务中应用了 TMS。在此任务中，中心箭头引导注意力转移，受试者通过按键对随后的视觉周边目标做出反应，而无需将眼睛从中心注视点移开。在一些试验中，提示无效或无信息，产生的反应比提示有效时慢。我们在目标出现前 53 毫秒或在目标出现后 70 毫秒发出单脉冲。与我们的预测相反，刺激的主要效果是在目标出现前 53 毫秒施加刺激时反应时间缩短。左半球的 TMS 仅在所有提示条件下促进对右半场目标的反应，而右半球的 TMS 对有效和中性提示具有双边效应，但对无效提示没有影响。因此，TMS 仅在右半球刺激的情况下干扰注意力转移：它增加了无效提示的成本。我们的结果表明，FEF 上的 TMS 有助于视觉检测，从而减少反应时间。这一发现为人类 FEF 在处理视觉信息中的作用提供了新的见解。在促进视觉检测和干扰注意力转移方面观察到的功能不对称性为右半球在这些过程中的主导地位提供了进一步的证据。我们的结果还强调，TMS 对特定区域的破坏性或促进性作用取决于行为背景。
When looking at one object, human subjects can shift their attention to another object in their visual field without moving the eyes. Such shifts of attention activate the same brain regions as those involved in the execution of eye movements. Here we investigate the role of one of the main cortical oculomotor area, namely, the frontal eye field (FEF), in shifts of attention. We used transcranial magnetic stimulation (TMS), a technique known to disrupt transiently eye-movements preparation. We hypothesized that if the FEF is a necessary element in the network involved in shifting attention without moving the eyes, then TMS should also disrupt visuospatial attention.For each volunteer, we positioned the TMS coil over the probabilistic anatomical location of the FEF, and we verified that single pulses delayed eye movements. We then applied TMS during a visuospatial attention task. In this task, a central arrow directed shifts of attention and the subject responded by a keypress to a subsequent visual peripheral target without moving the eyes from the central fixation point. In a few trials, the cue was invalid or uninformative, yielding slower responses than when the cue was valid. We delivered single pulses either 53 msec before or 70 msec after target onset.Contrary to our prediction, the main effect of the stimulation was a decrease in reaction time when it was applied 53 msec before target onset. TMS over the left hemisphere facilitated responses to targets in the right hemifield only and for all cueing conditions, whereas TMS over the right hemisphere had a bilateral effect for valid and neutral but not invalid cueing. Thus, TMS interfered with shift of attention only in the case of right hemisphere stimulation: it increased the cost of invalid cueing.Our results suggest that TMS over the FEF facilitates visual detection, and thereby reduces reaction time. This finding provides new insights into the role of the human FEF in processing visual information. The functional asymmetry observed for both facilitation of visual detection and interference with shifts of attention provides further evidence for the dominance of the right hemisphere for those processes. Our results also underline that the disruptive or facilitative effect of TMS over a given region depends upon the behavioral context.