Effects of perinatal PCB exposure on discrimination-reversal learning in monkeys.

Monkeys exposed to PCB mixtures during gestation and lactation were tested on two-choice discrimination-reversal learning (DR). In Experiment 1, offspring of mothers fed 1.0 ppm Aroclor 1248, and offspring born 1.5 years after maternal exposure to 2.5 ppm Aroclor 1248 ended did not differ from controls on spatial, color or shape DR problems. In Experiment 2, offspring of mothers fed 0.25 or 1.0 ppm Aroclor 1016 and offspring born 3 years after maternal exposure to 2.5 ppm Aroclor 1248 ended were tested on the same spatial, color and shape problems, but a spatial problem with color and shape as irrelevant cues was inserted after the initial spatial problem. Performance of the high dose Aroclor 1016 offspring was impaired on the initial spatial problem, and facilitated on the shape problem. Performance of the Aroclor 1248 postexposure offspring was facilitated on the shape problem. This apparently facilitatory effect may represent a failure of PCB-exposed monkeys to learn the irrelevancy of the shape cue when it was initially presented.