The Role of Lateral Cortical Competition in Ocular Dominance Development

Lateral competition within a layer of neurons sharpens and localizes the response to an input stimulus. Here, we investigate a model for the activity dependentdevelopment of ocular dominance maps which allows to vary the degree of lateral competition. For weak competition, it resembles acorrelation-based learning model and for strong competition, it becomes a self-organizing map. Thus, in the regime of weak competition thereceptive fields are shaped by the second order statistics of the input patterns, whereas in the regime of strong competition, the higher moments and "features" of the individual patterns become important. When correlated localized stimuli from two eyes drive the cortical development wefind (i) that a topographic map and binocular, localized receptive fields emerge when the degree of competition exceeds a critical value and (ii) that receptive fields exhibit eye dominance beyond a second criticalvalue. For anti-correlated activity between the eyes, the second orderstatistics drive the system to develop ocular dominance even for weak competition, but no topography emerges. Topography is established onlybeyond a critical degree of competition.