Department of Neurology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taipei 10507, Taiwan.
J Neurosci. 2011 Nov 2;31(44):15904-13. doi: 10.1523/JNEUROSCI.2626-11.2011.
While the frontal eye fields (FEF) are traditionally associated with eye movements, recent work indicates possible roles in controlling selective visual processing. We applied 10 Hz bursts of transcranial magnetic stimulation (TMS) over left or right human FEF while subjects performed a partial-report task that allowed quantitative estimates of top-down control and other parameters affecting visual performance. Participants selectively reported digits in a relevant color (targets) but not those in an irrelevant color (nontargets) from a brief masked display. A target could appear alone or together with an accompanying item (nontarget or target) in the same or opposite hemifield. Targets were normally identified better when presented with a nontarget than with another target, indicating prioritization of task-relevant targets and thus top-down control. We found this usual pattern of results without TMS, and also with TMS over left FEF. However, during right FEF TMS, the detrimental impact of accompanying distractors increased. Formal analysis in terms of Bundesen's (1990) theory of visual attention confirmed that right FEF TMS diminished the top-down control parameter for both hemifields, indicating an FEF role in top-down selection even for targets defined by the nonspatial property of color. Direct comparison with our previous findings for parietal TMS (Hung et al., 2005) confirmed the distinct role of FEF in top-down control, plus right-hemisphere predominance for this in humans.
虽然额眼区（FEF）传统上与眼球运动有关，但最近的研究表明，它可能在控制选择性视觉处理方面发挥作用。我们在受试者执行部分报告任务时，应用 10Hz 的经颅磁刺激（TMS）脉冲刺激左侧或右侧人类额眼区，该任务允许对自上而下的控制和影响视觉表现的其他参数进行定量估计。参与者从短暂的掩蔽显示中选择性地报告相关颜色的数字（目标），而不是不相关颜色的数字（非目标）。目标可以单独出现，也可以与同一或相反半视野中的伴随项目（非目标或目标）一起出现。当与非目标一起呈现时，目标通常比与另一个目标一起呈现时更容易识别，这表明任务相关目标的优先级和自上而下的控制。我们在没有 TMS 的情况下发现了这种通常的结果模式，并且在左侧 FEF 的 TMS 下也发现了这种模式。然而，在右侧 FEF 的 TMS 期间，伴随干扰物的不利影响增加了。根据 Bundesen（1990）的视觉注意理论进行的正式分析证实，右侧 FEF 的 TMS 降低了两个半视野的自上而下控制参数，这表明 FEF 在自上而下的选择中发挥作用，即使对于由颜色的非空间属性定义的目标也是如此。与我们之前对顶叶 TMS 的发现（Hung 等人，2005）进行的直接比较证实了 FEF 在自上而下的控制中具有独特的作用，并且在人类中右半球占主导地位。
