Shuttlebox Sidman avoidance in rhesus monkeys: day of week and amphetamine effects

Due to its stability and sensitivity, the Sidman avoidance schedule has been often used to characterize the psychotropic effects of drugs. In the present study, the effects of d-amphetamine (0.125, 0.25, and 0.5 mg/kg IM) on shuttlebox Sidman avoidance by rhesus monkeys were investigated. Amphetamine resulted in increased avoidance rates as shown by both bin and mean inter-response time (IRT) analyses. These results demonstrate the potential usefulness of this combination of task, species, and apparatus for investigating the effects of psychotropic substances. In addition, analysis of baseline data indicated a small but significant day of week effect with more efficient performance at the end of the week. The implications of this finding for conducting drug studies involving repeated measurements (i.e., cross-over designs) are discussed.