Figure 1.

(A) Illustration of the connectionist model. The input layer, containing eight nodes, is shown on the far right; the two layers of stimulus representations (perirhinal cortex [PRh] and caudal) are shown to the left of the input layer. Stimulus inputs to the network have eight “stimulus dimensions” (attributes); each dimension is represented in the diagram by an individual input node. On the caudal layer, stimulus dimensions are paired into four simple conjunctions. Each simple conjunction is shown in a different shade of gray and is represented individually on the caudal layer. On the perirhinal cortex layer, the eight stimulus dimensions are combined into a conjunction, shown in gray, which represents the whole stimulus. (B) Performance of the model during object recognition in two conditions, control and configural. Filled circles represent recognition of the control group, and open circles represent recognition scores of the lesion group. (C) Stimulus representations on the Kohonen grids of the model in the choice phase for the control (left) and configural (right) object recognition conditions. The PRh layer represents the object stimulus with a single conjunctive representation. The caudal layer represents individual object features separately; stimulus representations in the caudal layer are shown as chunked according to object “features,” i.e., half an object stimulus. Small circles indicate sharply tuned (“familiar”) representations, and large circles indicate coarsely tuned (“unfamiliar”) representations. For discussion, see Results.