Effect of postweaning nutritional and environmental restrictions on discrimination learning in albino rats.

Charles Foster littermate albino rats (72) were randomized into 9 independent groups in a 3 x 3 factorial design by varying nutrition and environment each at three levels: normal nutrition, 25% nutritional restriction and 50% nutritional restriction; normal environment, 3-week environmental restriction and 6-week environmental restriction. The nutritional and environmental restrictions were imposed from the 30th day of life for 6 weeks. The animals were subsequently tested for black/white original learning followed by reversal discrimination learning in a T-maze. The results indicated significant main effects for nutrition and environment on indices of learning ability. However, the nutrition x environment interaction was not significant. Post hoc analysis revealed that moderate and severe nutritional restriction as well as long-term environmental restriction caused significant discrimination learning deficits. Short-term environmental restriction failed to produce significant effect on learning behaviour. The results are discussed in context of environmental stress effects, altered brain mechanisms and psychological changes such as increased drive level and emotionality of the animal.

Effect of nutritional and environmental restrictions on discrimination learning behaviour of juvenile rats.

Effects of nutritional and environmental restrictions on discrimination learning in a single unit black/white T-maze were studied in albino rats. Nutritional restrictions were imposed by 25 and 50% dietary restriction and environmental restrictions were given for 3 and 6 weeks. Both the restrictions were imposed at 46th day after birth. Long-term (6 weeks) environmental restriction significantly impaired the original and reversal discrimination learning, however, short-term (3 weeks) restriction had no effect. Nutritional (dietary) restrictions, on the other hand, had no effect on both learning performances. Interaction between these two variables was also statistically insignificant.