[Mechanisms of visual generalization]

The phenomenon of differentiations transfer from grids of different frequency and orientation to bars of different width and orientation was examined by the method of alimentary motor conditioned reflexes elaborated in free behaving dogs. After formation of differentiations of rectangular high-contrast grids by spatial frequency or orientation, transfer to single lines with the width equal to the width of bars forming the grids, leads to a broadening of the range of frequencies and orientations eliciting a positive response. Due to this fact, differentiations disappear or considerably worsen. The obtained results do not agree with the detector hypothesis according to which a part of receptive fields of the visual cortex are detectors of borders or bars of different width and orientation. But the results are predicted quantitatively by the hypothesis of description of images by receptive fields of the visual cortex as by two-dimensional filtres tuned to different spatial frequencies and orientations.