DRUG DISCRIMINATION-TRAINING WITH LOW-DOSES - MAINTENANCE OF DISCRIMINATIVE CONTROL

Procedures are reported that maintain control by the drug cue during a nd after drug discrimination training with lower doses that yield pred ominantly vehicle-appropriate choices. Twelve pigeons were trained to discriminate chlordiazepoxide (CDP) from saline using two-key (drug vs . vehicle) drug discrimination procedures. Intermixed within each bloc k of 30 sessions were nine sessions of training with 8.0 mg/kg CDP, ni ne with one of seven lower training doses (4.0, 2.8, 2.0, 1.4, 1.0, 0. 7, or 0.5 mg/ kg CDP), and 12 with saline. The lower training dose was decreased across blocks. The three lowest training doses (1.0, 0.7, a nd 0.5 mg/kg CDP) yielded predominantly saline-appropriate choices but had no effect on discrimination of 8.0 mg/kg CDP or saline. Three dos es (2.0, 1.4, and 1.0 mg/kg CDP) were retrained, and each yielded perc entages of drug-appropriate choices nearly identical to those obtained during previous training. This drug discrimination procedure maintain s control by the drug cue during and after training with vehicle-like doses of the training drug and may allow for repeated assessment of ef fects of low training doses.