Previous studies demonstrate that frontal and parietal cortices are involved in bottom-up and top-down attentional processes. However, their respective contribution to these processes remains controversial. The purpose of the current study was to compare the causal contribution of frontal and parietal cortices to the control of bottom-up and top-down visual attention using functional magnetic resonance imaging (fMRI) and repetitive transcranial magnetic stimulation (rTMS). Subjects performed visual search for targets that were easy (pop-out) or difficult (non-pop-out) to distinguish from distractors. Three sites of interest were used, based on the individual fMRI activation during the performance of a search task: the right dorsolateral prefrontal cortex (rDLPFC), the right frontal eye field (rFEF) and the right superior parietal lobule (rSPL). Online rTMS stimulation, with the search onset, showed that relative to rTMS over the vertex, rTMS over the rDLPFC, the rFEF and the rSPL increased the search reaction time (RTs) in the non-pop-out condition. In comparison, no TMS effect was found in the pop-out condition. In addition, the search RT cost caused by the non-pop-out condition was larger after the rDLPFC-TMS compared to the vertex-TMS. The findings suggest that the frontal and parietal cortical regions are both involved in attentional processing during top-down visual search, and that the rDLPFC is causally related to the executive control of cognitive load increases between the pop-out and the non-pop-out search.

中文翻译：

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使用fMRI指导的TMS评估额叶顶叶皮质对自下而上和自上而下的视觉注意力控制的因果关系。

先前的研究表明额叶和顶叶皮层参与了自下而上和自上而下的注意过程。但是，它们各自对这些过程的贡献仍然存在争议。本研究的目的是使用功能磁共振成像（fMRI）和重复经颅磁刺激（rTMS）比较额叶和顶叶皮层对控制自下而上和自上而下的视觉注意力的因果关系。受试者进行视觉搜索，以寻找容易与干扰物区分开的目标（弹出）或困难（非弹出）。根据执行搜索任务时单个功能磁共振成像的激活情况，使用了三个感兴趣的位点：右背外侧前额叶皮层（rDLPFC），右额眼视野（rFEF）和右上壁小叶（rSPL）。具有搜索开始的在线rTMS刺激显示，相对于顶点上的rTMS，相对于rDLPFC的rTMS，rFEF和rSPL，在非弹出条件下增加了搜索反应时间（RTs）。相比之下，在弹出条件下未发现TMS效果。另外，rDLPFC-TMS后由非弹出条件引起的搜索RT成本要比顶点-TMS大。这些发现表明，在自上而下的视觉搜索过程中，额叶皮层和顶叶皮层区域都参与了注意处理，并且rDLPFC与弹出式和非弹出式之间认知负荷增加的执行控制有因果关系搜索。在非弹出条件下，rFEF和rSPL增加了搜索反应时间（RTs）。相比之下，在弹出条件下未发现TMS效果。另外，rDLPFC-TMS后由非弹出条件引起的搜索RT成本要比顶点-TMS大。这些发现表明，在自上而下的视觉搜索过程中，额叶皮层和顶叶皮层区域都参与了注意处理，并且rDLPFC与弹出式和非弹出式之间认知负荷增加的执行控制有因果关系搜索。在非弹出条件下，rFEF和rSPL增加了搜索反应时间（RTs）。相比之下，在弹出条件下未发现TMS效果。另外，rDLPFC-TMS后由非弹出条件引起的搜索RT成本要比顶点-TMS大。这些发现表明，在自上而下的视觉搜索过程中，额叶皮层和顶叶皮层区域都参与了注意处理，并且rDLPFC与弹出式和非弹出式之间认知负荷增加的执行控制有因果关系搜索。