Effects of undernutrition on the visually evoked responses in rats during development

Abstract

Effects of postnatal undernutrition on the maturation of the visually evoked responses (VERs) were investigated in rats. The VERs were recorded from the surface of the visual cortex in response to a flash of light. In the normal animals as age advanced, various components of the response appeared, their latencies shortened with an augmentation of their amplitude. The ability to follow repetitive stimulation at higher frequencies was also found to increase with age. In the undernourished rats, the appearance of the first positive wave (P₁) was delayed, the latencies of P₁ and the first negative wave (N₁) were prolonged and the amplitudes were smaller as compared with their normal counterparts. These animals were unable to follow repetitive stimulation at higher frequencies. Though protein-calorie malnutrition retarded the ontogenetic maturation of the visual system, rehabilitation led to a significant 'catch up'.