The objectives of the proposed research focus upon the development and application of laboratory procedures for the experimental analysis of effects produced by drugs of abuse upon auditory and visual sensitivity and reaction time in non-human primates. The validity, reliability, sensitivity, and specificity of animal psychophysical methodologies for the measurement of such effects will be evaluated experimentally. A series of studies will be conducted with dog-faced baboons to characterize and compare a range of abuseable drugs, does, and drug classes, including prototypical barbiturates, benzodiazepines, opiates, stimulants, and hallucinogens. Additionally, the effects of long-term recurrent exposure to such compounds in the context of a drug self-administration procedural model will provide for intermittent assessment of sensorimotor changes over extended time periods.