Temporal aspects of visual search studied by transcranial magnetic stimulation
Temporal aspects of visual search studied by transcranial magnetic stimulation
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DOI：
10.1016/s0028-3932(97)00003-1
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发表时间：
1997-08-01
期刊：
影响因子：
2.6
通讯作者：
Cowey, A
中科院分区：
文献类型：
--
作者：
Ashbridge, E;Walsh, V;Cowey, A
当受试者在包含八个干扰物的阵列中执行“弹出式”或联合视觉搜索任务时，经颅磁刺激被应用于顶叶视觉皮层。磁刺激对弹出搜索的表现没有不利影响，但当在视觉显示开始100毫秒后，当目标存在时，对右侧顶叶皮层施加磁刺激，会显著增加连接搜索的反应时间。靶缺失反应时间在阵列启动160 msec后增加。刺激对出错次数没有影响。结果表明，右顶叶的一个子区域对连接搜索很重要，但对预先注意弹出并不重要。目标实验的结果与猴子单细胞研究的时间数据一致，也与顶叶区域产生的信号投射回外皮层视觉区域以增强视野有限部分特征处理的假设一致。这种效应的发生时间表明，经颅刺激破坏了联合搜索中特征绑定所必需的焦点注意的潜在机制。经颅磁刺激对目标缺失试验的影响可以从额顶叶连接和额皮质在决策中的作用来解释。结果还强调了经颅磁刺激作为其他空间和时间成像技术的补充的有效性。1997爱思唯尔科学有限公司
Transcranial magnetic stimulation was applied over the parietal visual cortex of subjects while they were performing 'popout' or conjunction visual search tasks in arrays containing eight distracters. Magnetic stimulation had no detrimental effect on the performance of pop-out search, but did significantly increase reaction times on conjunction search when stimulation was applied over the right parietal cortex 100 msec after the onset of the visual display for trials when the target was present. Target absent reaction times were elevated when stimulation was applied 160 msec after array onset. Stimulation had no effect on the number of errors made. The results suggest that a sub-region of the right parietal lobe is important for conjunction search but not for preattentive pop-out. The result from target present trials is consistent with timing data from studies of single cells in monkeys and the hypothesis that parietal areas generate a signal that projects back to extrastriate visual areas to enhance the processing of features in a restricted part of the visual field. The timing of the effect indicates that transcranial stimulation disrupts the mechanisms underlying the focal attention necessary for feature binding in conjunction search. The effects of TMS on target absent trials are interpreted in terms of fronto-parietal connections and the role of frontal cortex in decision-making. The results also highlight the efficacy of transcranial magnetic stimulation as a complement to other spatial and temporal imaging techniques. (C) 1997 Elsevier Science Ltd.