Effects of pupillary responses to luminance and attention on visual spatial discrimination
Effects of pupillary responses to luminance and attention on visual spatial discrimination
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DOI：
10.1167/18.11.6
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发表时间：
2018-10-01
影响因子：
1.8
通讯作者：
Lorenceau, Jean
中科院分区：
文献类型：
--
作者：
Ajasse, Suzon;Benosman, Ryad B.;Lorenceau, Jean
眼睛的视觉质量至少在一定程度上是由瞳孔大小决定的。大瞳孔让更多的光线进入眼睛，但降低了点扩散函数，从而降低了可以实现的空间分辨率（Campbell & Gregory, 1960）。在自然条件下，瞳孔主要受凝视位置的亮度（也可能是颜色和对比度）驱动，但也受注意力和认知因素的调节。在两个实验中，我们评估了与亮度和注意力调节瞳孔大小相关的眼睛光学变化是否影响视觉加工。在实验1中，我们使用由四个不同亮度的圆盘组成的持续可见显示器来测量瞳孔大小，除了连续固定圆盘外没有其他任务。结果证实瞳孔大小取决于被凝视刺激的亮度。实验2使用与实验1相似的设置，采用双间隔强迫选择设计来测试是否在注视瞳孔较小的明亮圆盘时，需要隐蔽注意旁中央凹刺激的高空间频率辨别效果更好，因此眼睛的光学性能更好，而注视瞳孔较大的暗圆盘时，眼睛的光学性能较差。与实验1一样，我们观察到瞳孔大小随凝视刺激的亮度而发生较大的变化，但瞳孔动态变化更大，在刺激编码过程中瞳孔扩张明显，这可能是因为要求高的空间频率识别任务需要注意。然而，辨别能力与平均瞳孔大小不相关。尽管缺乏相关性，但刺激编码过程中的瞳孔扩张斜率与表现相关，而决策过程中的瞳孔扩张斜率则与表现无关。我们讨论这些结果关于瞳孔大小调节可能的功能角色。
The optic quality of the eyes is, at least in part, determined by pupil size. Large pupils let more light enter the eyes, but degrade the point spread function, and thus the spatial resolution that can be achieved (Campbell & Gregory, 1960). In natural conditions, the pupil is mainly driven by the luminance (and possibly the color and contrast) at the gazed location, but is also modulated by attention and cognitive factors. Whether changes in eyes' optics related to pupil size modulation by luminance and attention impacts visual processing was assessed in two experiments. In Experiment 1, we measured pupil size using a constantly visible display made of four disks with different luminance levels, with no other task than fixating the disks in succession. The results confirmed that pupil size depends on the luminance of the gazed stimulus. Experiment 2, using similar settings as Experiment 1, used a two-interval forced-choice design to test whether discriminating high spatial frequencies that requires covert attention to parafoveal stimuli is better during the fixation of bright disks that entails a small pupil size, and hence better eyes' optics, as compared to fixating dark disks that entails a large pupil size, and hence poorer eyes' optics. As in Experiment 1, we observed large modulations of pupil size depending on the luminance of the gazed stimulus, but pupil dynamics was more variable, with marked pupil dilation during stimulus encoding, presumably because the demanding spatial frequency discrimination task engaged attention. However, discrimination performance and mean pupil size were not correlated. Despite this lack of correlation, the slopes of pupil dilation during stimulus encoding were correlated to performance, while the slopes of pupil dilation during decision-making were not. We discuss these results regarding the possible functional roles of pupil size modulations.