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Fig. 13.20. Orientation selectivity in SMAP with different input distributions. For each of the four networks, the selectivity of neurons in the SMAP was measured (as described in Appendix G.1.3) and plotted as a histogram; GMAP selectivities were similar and are not shown. (a) The histogram for the 100% presentation frequency peaks at around 0.32, and that of the 50% frequency around 0.12, suggesting that the responses of the high-frequency network are sparser but stronger for specific inputs. (b) The histogram for the high curvature range [0^o..25^o] and the low curvature range [0^o..10^o] are almost identical. Given that the orientation preferences were also almost identical, any differences in their performance are likely to be due to the lateral connections.