Measurement of stress is imperative to psychological and mental disorder mouse model characterization, especially to determine the efficacy of drugs. Yet, conventional behavioral testing relies on indirect measures of stress that are difficult to interpret, time-intensive, and incompatible with concurrent electrophysiology, live imaging, or optogenetics.

University of Utah researchers have developed a protocol, paradigm, and apparatus to measure acute pupil dilation as a quantitative measure of mouse stress. The test is run in a sound and light isolated box, where tones are played to startle the mice. The apparatus is head-fixed, enabling concurrent high-resolution testing of brain activity.