DRUG EFFECTS ON RESPONSE-DURATION DIFFERENTIATION .4. EFFECTS OF TRIMETHYLTIN

Trimethyltin (TMT) is a toxicological agent that produces damage in a number of limbic structures, resulting in concomitant disruptions of b ehavior. The purpose of the present study was to determine the utility of response-duration differentiation (RDD) responding as a behavioral baseline for studying the behavioral consequences of TMT administrati on. Under the RDD schedule, responses of a restricted duration (1-1.3 s) were reinforced, and disruption of this performance may represent e ffects upon fine motor control, timing behavior, or both. Two doses of TMT (4 mg/kg) were administered 1 week apart, and behavior under the schedule was studied daily for 6 weeks thereafter in a group of four r ats. Additionally, the effects of diazepam (0.1-3 mg/kg) administered prior to and following TMT administration were compared. TMT produced disruptions in accuracy of responding and increases in rates of respon ding in the weeks following its administration. Behavior had generally recovered by 6 weeks after the first TMT administration. Diazepam fla ttened the relative frequency distributions of response durations at l ower doses in the TMT-treated rat. These data show that RDD responding is sensitive to the effects of TMT, and that TMT treatment can result in alterations in the effects of diazepam.