Homology of assessment of visual function in human and animal models

To connect animal models with human neurobehavioral evaluations, it is necessary to understand the level of homology present between tests administered across species. This paper identifies four different levels of homology of assessment based on identity of measurement, function, and underlying neural substrate. These are discussed using detailed examples from toxicology of the visual system, with additional examples from tests of motor and cognitive function. This should provide a framework for considering both animal to human extrapolation and human to animal extrapolation, that is, how to import human experimental epidemiology findings into the lab for further work investigating mechanisms of toxicity. Designing neurobehavioral or sensory evaluations that permit easier extrapolation between human and animal models is necessary if we are to develop testing strategies that take advantage of mechanistic information at whole animal, in vitro, proteonomic, or genomic levels.