In a recent survey of published animal studies, researchers found disregarding the animals’ circadian rhythms can hamper reproducibility, reliability and validity.

According to a new analysis out of West Virginia University, that’s often what it’s like to be a rodent in a biomedical study. Mice and rats, which make up the vast majority of animal models, are nocturnal. Yet a survey of animal studies across eight behavioral neuroscience domains showed that most behavioral testing is conducted during the day, when the rodents would normally be at rest.

«There are these dramatic daily fluctuations — in metabolism, in immune function, in learning and memory, in perception — and by the large, they get ignored,» said Randy Nelson, who led the study. «You just have to wonder: to what extent is that affecting the outcomes?»

Nelson chairs the School of Medicine’s Department of Neuroscience and directs basic science research for the Rockefeller Neuroscience Institute.

His findings appear in Neuroscience and Behavioral Reviews.

Nelson and his colleagues — RNI researchers Jacob Bumgarner, William Walker and Courtney DeVries — examined the 25 most frequently cited papers in each of eight categories of rodent behaviors: learning and memory, sensation and perception, attention, food intake, mating, maternal behavior, aggression and drug seeking.

Story Source:
Materials provided by West Virginia University. Note: Content may be edited for style and length.