Dimensionality of the intermediate-level representation of shape and texture in monkey V4.

The visual area V4 has been considered to play a crucial role in the intermediate representation of objects, where low-level image features are transformed into object-level representations. We estimated the intrinsic dimensionality in V4 for the representation of local patches generated from natural scenes. The dimensionality was approximately 40, which is approximately half of that reported in IT for the representation of whole natural objects. The analyses of the estimated dimensionality suggest both common and independent representations that code contour shapes and/or surfaces with textures, implying a relatively complex and mixed representation in the intermediate-level area.