A bright light, which would normally be expected to trigger pupil contraction, might also spill over to neighbouring sites, such as nerve fibres or neurons that carry nose-tickling sensations.

• 一道通常被认为引起瞳孔收缩的明亮的光线，也可溢出到相邻区，如传递鼻子反馈感觉的神经纤维或神经元。