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It makes sense that neuronal development would be dually influenced by genetic predispositions and by the actual process of making synaptic connections. The visual system is particularly subject during a baby's early development, as sight gradually comes into focus, and novel visual stimuli seem to figure largely in this process.

According to research, a child's nutrition can also determine the course of brain development, especially when it comes to the visual system. Babies who are breastfed show enhanced stereoscopic vision, and generally have visual systems that are more mature than their formula fed coevals. The scientific establishment to this day has not elucidated the complete chemical composition of breastmilk, but included Omega-3 fatty acids are known factors in visual development. One particularly, docosahexanoic acid (DHA), has been widely implicated for this role, although recent trials have suggested that formula supplemented with DHA and arachidonic acid fails to produce the dramatic developmental benefits of breastfeeding. Other studies have suggested that DHA and other long-chain polyunsaturated fatty acids contribute significantly to the development of visual acuity and the composition of plasma and erythrocyte phospholipids, but many suspect that other factors in human milk play a role in this nutrition.

Animal studies have investigated how the cerebral circuitry is tuned to stimuli in the environment. Each sight, sound or sensation experienced has been shown to refine the nerve-cell connections in a growing brain. However, certain complex organization in the mammalian brain is thought to develop without significant experiential reliance. In a recent study, designed to describe the development of the brain's visual neural network, modular and axial specificity was observed in the brains of very young tree shrews. On the other hand, recent evidence that blockade of cortical but not of retinal activity prevents the development of clustered horizontal connections in ferrets clearly indicates that neuronal activity is required for the development of tangential connections. Similar results have been observed across both systems and species. It seems that the development of the mammalian brain lies somewhere very near the nature-nurture nexus.