Several factors may interact to determine the periodicity of ocular dominance stripes in cat and monkey visual cortex. Previous theoretical work has suggested roles for the width of cortical interactions and the strength of between-eye correlations. Here, a model based on an explicit optimization is presented that allows a thorough characterization of how these and other parameters of the afferent input could affect ocular dominance stripe periodicity. The principle conclusions are that increasing the width of within-eye correlations leads to wider columns, and, surprisingly, that increasing the width of cortical interactions can sometimes lead to narrower columns. 1 Introduction In cats, monkeys and humans, layer 4 of the primary visual cortex (V1) is divided up into alternating regions dominated by input from the left and right eyes (e.g. Hubel & Wiesel (1977)). These regions segregate from a spatially uniform pattern during development (Rakic, 1976; LeVay et al, 1978). A characte...