In this review article, Directors of Rodent Behavior Cores at NICHD-supported Intellectual and Developmental Disorders Research Centers (IDDRCs) and other behavioral core facilities offer their expertise for conducting rigorous mouse and rat behavioral assays. Behavioral assays have a reputation for high variability and, in practice, reaching consensus on methods has proven difficult because of the varieties of available equipment, and varying local conditions.
Importantly, the innate behavioral repertoire of mice and rats is influenced by a broad range of environmental factors, including aspects of parenting received from birth through weaning, dominance hierarchies in the home cage, amount of human handling prior to testing, previous testing experiences, olfactory cues from the investigators, and physical properties of the vivarium and laboratory such as lighting, temperature and noises. Many small but essential details affect the success of each rodent behavioral assay. To achieve maximal rigor and reproducibility of findings, well-trained investigators employ a variety of established best practices. In this article, the authors explicate some of the requirements for rigorous experimental design and accurate data analysis in conducting mouse and rat behavioral tests. Many of the principles presented in this paper are applicable across neuroscience research disciplines.