Both generalized arousal and engagement in a specific task influence sensory neural processing. To isolate effects of these state variables in the auditory system, we recorded single-unit activity from primary auditory cortex (A1) and inferior colliculus (IC) of ferrets during a tone detection task, while monitoring arousal via changes in pupil size. We used a generalized linear model to assess the influence of task engagement and pupil size on sound-evoked activity. In both areas, these two variables affected independent neural populations. Pupil size effects were more prominent in IC, while pupil and task engagement effects were equally likely in A1. Task engagement was correlated with larger pupil; thus, some apparent effects of task engagement should in fact be attributed to fluctuations in pupil size. These results indicate a hierarchy of auditory processing, where generalized arousal enhances activity in midbrain, and effects specific to task engagement become more prominent in cortex.

中文翻译：

---

听觉皮层和中脑的任务参与和唤醒效应的分离

全面唤醒和参与特定任务都会影响感觉神经处理。为了隔离这些状态变量在听觉系统中的作用，我们在声调检测任务中记录了雪貂的主要听觉皮层（A1）和下丘脑（IC）的单单位活动，同时通过瞳孔大小的变化监控唤醒。我们使用广义线性模型来评估任务参与度和瞳孔大小对诱发声音活动的影响。在这两个领域，这两个变量影响了独立的神经种群。学生的大小影响在IC中更为突出，而学生和任务投入的影响在A1中同样可能。任务投入与大学生有关；因此，任务参与的一些明显影响实际上应该归因于瞳孔大小的波动。