Tactile or visual?: Stimulus characteristics determine receptive field type in a self-organizing map model of cortical development

Tactile receptive fields (RFs) are similar to visual receptive fields, while there is a subtle difference. Our previous work showed that tactile RFs have advantage in texture boundary detection tasks compared to visual RFs. Our working hypothesis was that tactile RFs are better in texture tasks since texture is basically a surface property, more intimately linked with touch than with vision. From an information processing point of view, touch and vision are very similar (i.e., two-dimensional sensory surface). Then, the question is what drives the two types of RFs to become different? In this paper, we investigated the possibility that tactile RF and visual RF emerge based on an identical cortical learning process, where the only difference is in the input type, natural-scene-like vs. texture-like. We trained a self-organizing map model of the cortex (the LISSOM model) on two different kinds of input, (1) natural scene and (2) texture, and compared the resulting RFs. The main result is that RFs trained on natural scenes have RFs resembling visual RFs, while those trained on texture resemble tactile RFs. These results suggest that the type of input most commonly stimulating the sensory modality (natural scene for vision and texture for touch), and not the intrinsic organization of the sensors or the developmental process in the cortex, determine the RF property. We expect these results to shed new light on the differences and similarities between touch and vision.