Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Section Social Neuroscience, Department of General Psychiatry, University of Heidelberg, Heidelberg, Germany.
Eur J Neurosci. 2024 May;59(10):2686-2701. doi: 10.1111/ejn.16306. Epub 2024 Mar 12.
In everyday perception, we combine incoming sensory information with prior expectations. Expectations can be induced by cues that indicate the probability of following sensory events. The information provided by cues may differ and hence lead to different levels of uncertainty about which event will follow. In this experiment, we employed pupillometry to investigate whether the pupil dilation response to visual cues varies depending on the level of cue-associated uncertainty about a following auditory outcome. Also, we tested whether the pupil dilation response reflects the amount of surprise about the subsequently presented auditory stimulus. In each trial, participants were presented with a visual cue (face image) which was followed by an auditory outcome (spoken vowel). After the face cue, participants had to indicate by keypress which of three auditory vowels they expected to hear next. We manipulated the cue-associated uncertainty by varying the probabilistic cue-outcome contingencies: One face was most likely followed by one specific vowel (low cue uncertainty), another face was equally likely followed by either of two vowels (intermediate cue uncertainty) and the third face was followed by all three vowels (high cue uncertainty). Our results suggest that pupil dilation in response to task-relevant cues depends on the associated uncertainty, but only for large differences in the cue-associated uncertainty. Additionally, in response to the auditory outcomes, the pupil dilation scaled negatively with the cue-dependent probabilities, likely signalling the amount of surprise.
在日常生活中，我们会将输入的感官信息与先验期望结合起来。期望可以通过暗示后续感官事件概率的线索来产生。线索提供的信息可能不同，因此会导致对后续事件的不确定性水平不同。在这个实验中，我们使用瞳孔测量法来研究视觉线索引起的瞳孔扩张反应是否取决于与后续听觉结果相关的线索关联不确定性的水平。此外，我们还测试了瞳孔扩张反应是否反映了对随后呈现的听觉刺激的惊讶程度。在每个试验中，参与者都会看到一个视觉线索（面部图像），然后是一个听觉结果（元音发音）。在面部线索之后，参与者必须通过按键来指示他们期望听到接下来的三个元音中的哪一个。我们通过改变概率线索-结果关联来操纵线索关联的不确定性：一个面孔最有可能紧接着一个特定的元音（低线索不确定性），另一个面孔同样可能紧接着两个元音中的任意一个（中线索不确定性），而第三个面孔则紧接着三个元音（高线索不确定性）。我们的结果表明，对任务相关线索的瞳孔扩张反应取决于相关的不确定性，但仅在线索相关不确定性存在较大差异时才会如此。此外，对于听觉结果，瞳孔扩张与线索依赖性概率呈负相关，可能反映了惊讶程度。
