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Fig. 5.15. Self-organization of afferent weights into OD receptive fields. (a) The afferent weights of a sample neuron, located as shown in Figure 5.17a, are plotted before self-organization (as in Figure 5.5). Initially these weights are random and identical for both eyes and both channels in each eye. (b) The final receptive fields of the same neuron are visualized for each eye by subtracting the OFF weights from the ON weights (as in Figure 5.7). Over the course of self-organization, most neurons develop a preference for one eye or the other, although they retain significant connections from both eyes. Many of this neuron's connections from the left eye are weak (indicated by medium gray), so it responds more strongly to input in the right eye. (c) On the other hand, neurons near the OD stripe boundaries, like the one in Figure 5.17b, become strongly binocular, with smooth, isotropic RFs that are nearly identical in each eye. The ocular dominance stripes shown in Figure 5.16 are based on such subtle eye preferences, as they are in animal OD maps.