On the Role of Suppression in Spatial Attention: Evidence from Negative BOLD in Human Subcortical and Cortical Structures
On the Role of Suppression in Spatial Attention: Evidence from Negative BOLD in Human Subcortical and Cortical Structures
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DOI：
10.1523/jneurosci.0164-14.2014
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发表时间：
2014-07-30
影响因子：
5.3
通讯作者：
Morland, Antony B.
中科院分区：
文献类型：
--
作者：
Gouws, Andre D.;Alvarez, Ivan;Morland, Antony B.
有明确的证据表明，空间注意增加神经反应出席刺激外纹视觉区，并在较小程度上，在早期的视觉领域。其他证据表明，代表无人看管位置的神经元也会受到抑制。然而，在何种程度上增强和抑制观察到，他们的刺激依赖性，以及他们表达的视觉系统的阶段仍然知之甚少。使用功能磁共振成像，我们开始描述任务和刺激依赖的神经反应在外侧膝状体核（LGN），初级视觉皮层（V1），视觉运动区（V5）在人类中，以确定在抑制和促进空间注意力的影响表示。受试者观看偏侧漂移光栅刺激，在多个刺激对比，并执行三个任务之一，旨在改变他们的注意力的空间位置。在retinotopic表示的刺激位置，我们观察到增加注意力依赖的促进和减少依赖刺激对比度移动视觉层次从LGN到V5。然而，在LGN和V1的无人值守位置的表示，我们观察到抑制，这是不显着依赖于出席刺激对比度。这些抑制作用也发现在枕，这是经常与注意力。因此，我们提供的证据，空间选择性抑制机制，作用于皮层下水平。
There is clear evidence that spatial attention increases neural responses to attended stimuli in extrastriate visual areas and, to a lesser degree, in earlier visual areas. Other evidence shows that neurons representing unattended locations can also be suppressed. However, the extent to which enhancement and suppression is observed, their stimulus dependence, and the stages of the visual system at which they are expressed remains poorly understood. Using fMRI we set out to characterize both the task and stimulus dependence of neural responses in the lateral geniculate nucleus (LGN), primary visual cortex (V1), and visual motion area (V5) in humans to determine where suppressive and facilitatory effects of spatial attention are expressed. Subjects viewed a lateralized drifting grating stimulus, presented at multiple stimulus contrasts, and performed one of three tasks designed to alter the spatial location of their attention. In retinotopic representations of the stimulus location, we observed increasing attention-dependent facilitation and decreasing dependence on stimulus contrast moving up the visual hierarchy from the LGN to V5. However, in the representations of unattended locations of the LGN and V1, we observed suppression, which was not significantly dependent on the attended stimulus contrast. These suppressive effects were also found in the pulvinar, which has been frequently associated with attention. We provide evidence, therefore, for a spatially selective suppressive mechanism that acts at a subcortical level.