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BEHAVIORAL EVALUATION OF PERINATAL EXPOSURE TO AROCLOR 1254 IN RATS: FIXED-INTERVAL PERFORMANCE AND REINFORCEMENT-OMISSION.
Taylor, M. M., K M. Crofton, AND Macphail. BEHAVIORAL EVALUATION OF PERINATAL EXPOSURE TO AROCLOR 1254 IN RATS: FIXED-INTERVAL PERFORMANCE AND REINFORCEMENT-OMISSION. Presented at Neurobehavioral Teratology Society, West Palm Beach, FL, June 25-28, 2000.
Mele et al. (1986) reported exposure to Aroclor 1248 (A1248) in rhesus monkeys produced an increased rate of responding under a fixed-interval (FI) schedule of reinforcement in which 25% of the scheduled reinforcers were omitted. The purpose of this work was to determine whether a disruption in temporal patterning could be achieved following intervals in which reinforcers were omitted in rats perinatally exposed to A1254. Long Evans rats were exposed to 0 or 6mg/kg/day A1254 via oral gavage from Gestation Day 6 through Postnatal Day 21. At approximately Postnatal Day 90, the offspring were food deprived (85% free-feeding weight), then hand-shaped to lever press. Once the response was reliably emitted, the subjects were tested on several fixed-interval schedules of various interval length (FI30s, FI5min, FI5min with a tone which signaled reinforcer availability and FI3min). Then the subjects were placed on a FI3min schedule in which 33% of the scheduled reinforcers were omitted. There was an increase in the rate of responding and nosepokes as well as a decrease in the index of curvature, post-reinforcement pause and lock time following omission intervals. These results however, did not reveal a dose-related effect, suggesting that perinatal A1254 exposure in the rat does not disrupt temporally organized behavior.
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Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
NEUROBEHAVIORAL TOXICOLOGY BRANCH