Inconsistent results in Elevated Plus Maze (EPM) anxiety testing in C57BL/6 or BALB/c mice, and high variability between laboratories.

Standardize the EPM procedure to resolve behavioral variability: 1) Use diffuse, consistent lighting, or switch to infrared (IR) light with tracking software to allow testing in dim conditions. 2) Acclimate mice to the testing room for at least 1 hour before testing. 3) Thoroughly clean the maze with 70% ethanol between every animal to remove pheromonal cues. 4) Test male and female mice on different days to prevent pheromone-induced behavioral shifts. 5) Blind the experimenter to the genotype. Analyze protected versus unprotected head-dips and stretched-attend postures (SAP) for more sensitive anxiety readouts.