Anticipatory and stimulus-evoked blood oxygenation level-dependent modulations related to spatial attention reflect a common additive signal.
Anticipatory and stimulus-evoked blood oxygenation level-dependent modulations related to spatial attention reflect a common additive signal.
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与空间注意有关的预期和刺激诱发的血液氧合水平依赖性调制反映了常见的添加信号。
DOI：
10.1523/jneurosci.1141-09.2009
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发表时间：
2009-08-26
期刊：
影响因子：
--
通讯作者：
Corbetta M
中科院分区：
文献类型：
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作者：
Sylvester CM;Shulman GL;Jack AI;Corbetta M
内隐注意与视觉皮层的BOLD调制有关。在某些情况下，这种准备活动可以预测人类受试者对即将到来的视觉对象的感知程度。准备活动可能通过影响刺激诱发的反应来介导这种行为效应，但准备活动和刺激诱发的BOLD调制之间的关系尚不清楚。在这里，我们研究这种关系，通过比较空间注意力对预期和刺激诱发信号的影响，并通过测量前和后刺激调制之间的试验相关性。我们发现，在纹外视皮层（V4），调制相关的空间注意力是相对较大的，从刺激前通过诱发反应的峰值延伸，并在诱发反应相比，刺激前的反应略大。在纹状体皮层（V1），额叶眼场（FEF），和顶内沟（IPS），调制有关的空间注意力相对较小，主要局限于前刺激期，并略大于准备与刺激诱发的活动。重要的是，在整个视觉皮层中，准备活动和诱发活动中的注意力偏差（有人注意的位置与无人注意的位置的活动）比在休息时测量的受试者活动的基础上预期的更正相关。我们认为，这种模式的结果表明，相同的机制的基础准备和刺激诱发BOLD调制相关的空间注意和传入的感觉信号添加到预先存在的偏见在准备活动产生的刺激诱发的反应。
Covert attention is associated with pre-stimulus BOLD modulations in visual cortex. In some situations, this preparatory activity can predict how well human subjects will perceive upcoming visual objects. Preparatory activity may mediate this behavioral effect by affecting the stimulus-evoked response, but the relationship between preparatory and stimulus-evoked BOLD modulations is unclear. Here, we examine this relationship by comparing the effects of spatial attention on anticipatory and stimulus-evoked signals and by measuring the trial-to-trial correlation between pre- and post-stimulus modulations. We find that in extrastriate visual cortex (V4), modulations related to spatial attention are relatively large, extend from pre-stimulus through the peak of the evoked response, and are slightly larger in the evoked response compared to the pre-stimulus response. In striate cortex (V1), the frontal eye fields (FEF), and the intraparietal sulcus (IPS), modulations related to spatial attention are relatively small, are confined primarily to the pre-stimulus period, and are slightly larger in preparatory versus stimulus-evoked activity. Importantly, across visual cortex, the attentional biases (activity for attended versus unattended locations) in preparatory and evoked activity are more positively correlated, trial-by-trial, than would be expected on the basis of activity measured in subjects at rest. We argue that this pattern of results suggests that the same mechanisms underlie preparatory and stimulus-evoked BOLD modulations related to spatial attention and that incoming sensory signals add to pre-existent biases in preparatory activity to generate the stimulus-evoked response.