Neonatal low-level lead exposure in monkeys (Macaca fascicularis): effect on two-choice non-spatial form discrimination.

Monkeys were dosed orally with 500 microgram/kg/day of lead as lead acetate from day 1 of life. No overt signs of lead toxicity were observed. At 2--3 years of age they were tested on a two-choice non-spatial form discrimination using a WGTA apparatus. Treated monkeys showed deficits compared to controls on a series of 20 discrimination reversals; there was no difference between the groups in the effect of a series of "overtraining" trials introduced between reversals.