Early-life malnutrition impairs the performance of both young and adult rats on visual discrimination learning tasks

Previously malnourished young (20-40-day-old) and mature (70-77-day-old) rats were compared on position, brightness, and pattern discrimination problems using an aquatic version of the Lashley jump stand. Malnutrition did not affect performance on the position discrimination. In contrast, previously malnourished 24-34-day-olds failed to solve the brightness discrimination, 40-day-olds were impaired on the brightness problem, and 40-77-day olds were impaired on the pattern problem. The impaired performance of the 40-day-olds on the brightness problem was eliminated by prior training on the pattern discriminations, and the impaired performance of the 70-day-olds on the pattern discrimination could be eliminated if they were first trained on the brightness problem. These impairments were attributed to the effects of early-life malnutrition on the maturation of attention processes that enable the rat to suppress responding to irrelevant cues. The relevance of a contextual-organismic perspective for understanding the effects of early-life malnutrition was discussed.