Table 2

Summary of assays used to measure the anxiety phenotype in rodent models

Light/dark box assayBox apparatus is divided into two sections: the smaller dark “protected” side (minimally lit with black walls), and the larger light ‘unprotected’ side (brightly illuminated with white walls);
Relies on the principle of the innate aversion of a rodent to light and exposure to predators as a prey animals;
Shorter latency periods entering the light side, and/or longer periods spent here, are interpreted as reduced anxiety-like behaviors;
Measures the approach–avoidance behavior
Crawley and Goodwin, 1980;
Campos et al., 2013;
Lezak et al., 2017
EPM testConsists of two open, or unenclosed arms opposing two enclosed arms in the shape of a plus sign;
Apparatus is elevated several feet from the ground;
Animals are placed at the left of the EPM and allowed to explore freely for 5 min;
Exposure created by open arms is associated with anxiety-like behavior, such as increased defecation and corticosteroid levels;
More time spent in, as well as higher percentage of entries into the open arms of the EPM, are interpreted as reduced anxiety-like indices;
Measures approach–avoidance behaviors
Handley and Mithani, 1984;
Korte, 2001;
Campos et al., 2013;
Lezak et al., 2017
Open field testConsists of an open box divided into layers of rings from the left of the box to the corners;
The time spent in the middle where hypothetically the animal is most exposed and vulnerable, is compared with the amount of time spent hugging the safer corners of the box;
The number of times ventured towards the left of the box is also recorded;
Reduced anxiety is inferred if the animal tends to venture out from peripheral zones, or spend longer periods in the more central zones of the open box;
Relies on instinctual fear responses to predators 
Lezak et al., 2017