An important consideration for the IACUC, researcher, and veterinarian is the selection of the animal species to be used for behavioral screening in pharmacology and toxicology (Luft and Bode, 2002). Available data on kinetics and metabolism should be taken into consideration in identifying a species whose behavior will best predict effects in humans. Generally speaking, rodents are good models for behavioral screening in studies of neurotoxicity and neuropharmacology (Luft and Bode, 2002).

Some behavioral-toxicology experiments involve dosing that produces deleterious effects. The protocol should provide a contingency plan for conditions in which side effects will be alleviated or that require an animal’s removal from an experiment (see “Animal Care and Use Concerns Associated with Toxicity or Long-lasting Drug Effects” in Chapter 8).

Once a general health assessment of a newly developed strain of genetically modified animals is completed (see “Genetically Modified Animals” in Chapter 3), behavioral phenotyping should proceed as soon as sufficient numbers of transgenic animals are available to identify sensory, motor, or motivational deficits that may compromise animal well-being. Sensory and motor assessments should be completed before assessment of more complex behaviors—such as learning and memory, aggression, mating, and parental behaviors—because sensory and motor deficits may confound the interpretation of other behavioral assessments.

Behavioral tests assess the effects of altering, adding, or removing a gene (and gene product) on behavior, not the effects of the normal gene on behavior (Nelson, 1997). Behavioral phenotyping can also be confounded by impairments that are secondary to the missing or inserted gene; for example, knocking out a gene may cause the compensatory overexpression of a second gene and any changes in behavior could be the result of the overexpression of the second gene. Those possible problems can be overcome in the same way as in other types of