Figure 3.

Stage-one training causes primary weight vectors to cluster with primary input vectors. The distinctiveness of the clusters depends on primary input ambiguity. In A-C, there are twice as many modality-specific as cross-modal targets, and the spontaneous primary input activation probability p_x0 equals 0.1. The primary input becomes less ambiguous as the driven activation probability p_x1 is increased from 0.3 (A) to 0.6 (B) to 0.9 (C) (Table 3). Clusters of primary input vectors (circles) become progressively more distinct. This causes more primary weight vectors (plus signs) to adopt a distinctly unimodal pattern. V, Visual; A, auditory; S, somatosensory.