Use of activity measures in behavioral toxicology.

Locomotor activity measurements have been used extensively to evaluate chemically-induced changes in CNS function. This paper focuses on several factors including apparatus, age, biological rhythm, and social setting, which influence both locomotor activity levels per se and chemically induced changes in these activity levels. These data illustrate that failure to recognize, specify, and consider these factors is likely to result in equivocal studies subject to possible misinterpretation.