Guidelines for conducting neurobehavioral tests of motor activity, schedule-controlled operant performance, and a functional observational battery (FOB) were published by the U.S. EPA Office of Toxic Substances (1985). A specific FOB protocol has been utilized in conjunction with motor activity measured in a figure-eight maze and performance maintained under a fixed-interval schedule of reinforcement to determine the acute effects of chemicals which produce different syndromes of intoxication in rats (chlordimeform, carbaryl, pentobarbital, triadimefon, nicotine, and 3-acetyl pyridine). In all cases, the lowest effective dose identified using the FOB was equal to or less than that provided by motor activity and operant tests. For most compounds, motor activity and operant performance were equally sensitive. Nicotine and triadimefon, however, increased the rate of operant responding at doses lower than those required to affect motor activity. The time course of each chemical appeared similar across tests with one exception. 3-Acetyl pyridine produced clear effects in the FOB throughout testing (up to 3 weeks) whereas recovery was evident within one week using motor activity and operant performance. (Copyright (c) 1990 by Intox Press, Inc.)