Behavioral evaluation of perinatal PCB exposure in rhesus monkeys: fixed-interval performance and reinforcement-omission

Abstract

Two experiments were conducted to examine the prolonged behavioral effects of perinatal exposure to polychlorinated biphenyls (PCBs, Aroclor 1248) in rhesus monkeys. Experiment I involved testing a group of three monkeys whose mothers had been fed 2.5 ppm PCBs in their diets both before and throughout gestation and nursing (concurrent exposure condition), and a group of three control monkeys whose mothers had received no added dietary PCBs. These offspring began testing at approximately 60 months of age. In experiment II the same group of female breeders which were fed PCBs in experiment I underwent a second round of breeding after being off the contaminated diet for an average of 20 months (postexposure condition). Additionally, another group of female monkeys underwent breeding while receiving concurrent exposure to 0.5 ppm PCBs in their diet. Control female monkeys received no added dietary PCBs. Four offspring from the 2.5 ppm postexposure condition, four from the 0.5 ppm concurrent exposure condition and five control offspring survived to begin testing here at approximately 40 months of age. All monkeys from experiments I and II were tested under a series of fixed-interval schedules of food reinforcement consisting of FI 30 sec (10 sessions) and FI 60, 300 and 600 sec (15 sessions each). Performance measures included overall response rate, index of curvature (IC) and postreinforcement pause (PRP). There were no consistent differences in FI performance between PCB and respective control groups except for a slightly though significantly lower IC in the PCB groups of experiment II under FI 300 and 600.(ABSTRACT TRUNCATED AT 250 WORDS)