Department of Psychology, Durham University, Durham, United Kingdom.
Department of Psychology, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.
PLoS One. 2014 Apr 4;9(4):e93767. doi: 10.1371/journal.pone.0093767. eCollection 2014.
The existence of a network of brain regions which are activated when one undertakes a difficult visual search task is well established. Two primary nodes on this network are right posterior parietal cortex (rPPC) and right frontal eye fields. Both have been shown to be involved in the orientation of attention, but the contingency that the activity of one of these areas has on the other is less clear. We sought to investigate this question by using transcranial direct current stimulation (tDCS) to selectively decrease activity in rPPC and then asking participants to perform a visual search task whilst undergoing functional magnetic resonance imaging. Comparison with a condition in which sham tDCS was applied revealed that cathodal tDCS over rPPC causes a selective bilateral decrease in frontal activity when performing a visual search task. This result demonstrates for the first time that premotor regions within the frontal lobe and rPPC are not only necessary to carry out a visual search task, but that they work together to bring about normal function.
当人们进行困难的视觉搜索任务时，大脑区域的网络会被激活，这一点已经得到充分证实。该网络中有两个主要节点，分别是右后顶叶皮层（rPPC）和右额眼区。这两个区域都被证明与注意力的定向有关，但它们之间的活动关联还不太清楚。我们通过使用经颅直流电刺激（tDCS）选择性地降低 rPPC 的活动，然后让参与者在进行功能磁共振成像的同时执行视觉搜索任务，来研究这个问题。与应用假刺激的条件进行比较的结果表明，rPPC 的阴极 tDCS 会导致在执行视觉搜索任务时双侧额叶活动的选择性降低。这一结果首次证明，额叶和 rPPC 内的运动前区域不仅对执行视觉搜索任务是必要的，而且它们共同协作以实现正常功能。
