THE EFFECT OF THE ADMINISTRATION OF SODIUM BROMIDE TO PREGNANT RATS ON THE LEARNING ABILITY OF THE OFFSPRING

II. MAZE-TEST

¹ From the Department of Pharmacology and Toxicology of the Woman's Medical College of Pennsylvania and the Department of Psychology of Temple University, Philadelphia

1. Experiments were designed to test the hypothesis that sodium bromide administered during pregnancy would exert deleterious effects on the development of the nervous system of the offspring. One hundred and twenty-seven rats of the Wistar experimental strain were used. They were divided into 4 balanced groups; the control, composed of offspring of normal mothers; and three experimental groups whose mothers were dosed with 40, 80 and 120 mgm. of sodium bromide per day from the third through the twentieth day of gestation. The animals were tested on a 5 unit U-maze from 61-85 days of age and at this time were free of abnormal amounts of bromide.

2. The criterion of errors shows a positive relationship between the number of errors and the strength of the bromide-dosage.

3. The criterion of time shows that group "120" which received the largest dose of bromide was significantly slower than each of the other groups but the other groups did not differ among themselves.

4. All groups reached the same level of performance before the twenty-fifth day of the test. This fact suggested that in the maze-test the deleterious effects of the bromide appear in the rate of learning rather than in the performance finally attained.