Asymmetry of the pupillary light reflex during a cold pressor test

Pupillary light reflexes were monitored in 20 healthy participants while they immersed one foot in painfully cold water (the cold pressor test) or in warm water for 1  min. Pupillary dilatation was greater during the cold pressor test than during the warm-water immersion. In addition, during the cold pressor test, re-dilation after exposure to bright light proceeded more rapidly for the ipsilateral than contralateral pupil. These findings suggest that sympathet ic pupillary drive is greater ipsilateral than contralateral to pain.
Source: Autonomic Neuroscience: Basic and Clinical - Category: Neuroscience Authors: Tags: Short Communication Source Type: research