Push-pull mechanism of selective attention in human extrastriate cortex
Push-pull mechanism of selective attention in human extrastriate cortex
复制标题
DOI：
10.1152/jn.00974.2003
复制
发表时间：
2004-07-01
影响因子：
2.5
通讯作者：
Kastner, S
中科院分区：
文献类型：
--
作者：
Pinsk, MA;Doniger, GM;Kastner, S
选择性注意在视觉皮质中发挥作用，促进对选定刺激的处理，并过滤掉视觉空间有限区域附近干扰物中不需要的信息。在这个注意力焦点之外，未被注意的刺激的神经表征还不太清楚。我们研究了神经命运的无人值守的刺激，使用功能性磁共振成像分离的活动引起的出席（目标）刺激的外围的视觉半野和无人值守（分心）的刺激同时提出了相应的位置对侧半野。受试者隐蔽地将注意力指向一系列目标刺激，并对一系列相同的刺激进行低或高注意力负荷搜索任务。在这项任务中，目标搜索相关的活动增加与注意力负荷的增加，而分心相关的活动减少与负荷的增加，在V4和TEO区，但不是在早期的V1和V2区。这一发现提供了证据的负载依赖性推拉机制的选择性注意，在大部分的视野在中间处理阶段。这种机制似乎是由一个分布式的额顶叶网络的大脑区域，反映了空间定向注意过程中的目标选择相关的过程。
Selective attention operates in visual cortex by facilitating processing of selected stimuli and by filtering out unwanted information from nearby distracters over circumscribed regions of visual space. The neural representation of unattended stimuli outside this focus of attention is less well understood. We studied the neural fate of unattended stimuli using functional magnetic resonance imaging by dissociating the activity evoked by attended ( target) stimuli presented to the periphery of a visual hemifield and unattended ( distracter) stimuli presented simultaneously to a corresponding location of the contralateral hemifield. Subjects covertly directed attention to a series of target stimuli and performed either a low or a high attentional-load search task on a stream of otherwise identical stimuli. With this task, target-search-related activity increased with increasing attentional load, whereas distracter-related activity decreased with increasing load in areas V4 and TEO but not in early areas V1 and V2. This finding presents evidence for a load-dependent push-pull mechanism of selective attention that operates over large portions of the visual field at intermediate processing stages. This mechanism appeared to be controlled by a distributed frontoparietal network of brain areas that reflected processes related to target selection during spatially directed attention.