How do attention and adaptation affect contrast sensitivity?
How do attention and adaptation affect contrast sensitivity?
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DOI：
10.1167/7.7.9
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发表时间：
2007-01-01
影响因子：
1.8
通讯作者：
Carrasco, Marisa
中科院分区：
文献类型：
--
作者：
Pestilli, Franco;Viera, Gerardo;Carrasco, Marisa
注意和适应都是优化视觉表现的机制。注意通过增加对有注意刺激的对比敏感度和神经反应而降低对无注意刺激的对比敏感度和神经反应来优化表现；适应通过增加对变化刺激的对比敏感度和神经反应而降低对不变刺激的对比敏感度和神经反应来优化性能。我们研究了适应状态和注意对对比敏感度的影响是否相互作用以及如何相互作用。我们在两种适应条件下——适应0%或100%的对比度——集中、分散和退缩的注意条件下，用定向辨别任务测量了对比敏感度。我们使用阈值和渐近表现来衡量在适应高对比度刺激之前和之后的注意效应（增强或损害对比敏感性）的程度。结果表明，注意和适应以相似但相反的方式影响对比心理测量功能：注意增加刺激显著性，而适应降低刺激显著性。一个有趣的发现是，适应状态并不调节注意效应的大小。这表明，一旦对比度适应效应发生，注意就会影响归一化信号，这两种机制分别作用于对比度敏感性的改变。注意可以克服适应来恢复对比敏感度。
Attention and adaptation are both mechanisms that optimize visual performance. Attention optimizes performance by increasing contrast sensitivity for and neural response to attended stimuli while decreasing them for unattended stimuli; adaptation optimizes performance by increasing contrast sensitivity for and neural response to changing stimuli while decreasing them for unchanging stimuli. We investigated whether and how the adaptation state and the attentional effect on contrast sensitivity interact. We measured contrast sensitivity with an orientation-discrimination task, in two adaptation conditions-adapt to 0% or 100% contrast-in focused, distributed, and withdrawn attentional conditions. We used threshold and asymptotic performance to index the magnitude of the attentional effect-enhancement or impairment in contrast sensitivity-before and after adapting to high-contrast stimuli. The results show that attention and adaptation affect the contrast psychometric function in a similar but opposite way: Attention increases stimulus salience, whereas adaptation reduces stimulus salience. An interesting finding is that the adaptation state does not modulate the magnitude of the attentional effect. This suggests that attention affects the normalized signal once the effect of contrast adaptation has taken place and that these two mechanisms act separately to change contrast sensitivity. Attention can overcome adaptation to restore contrast sensitivity.