Brain mechanisms of visual form perception
Abstract: The perception of complex visual patterns emerges from neuronal activity in a cascade of areas in the primate cerebral cortex. Neurons in the primary visual cortex, V1, represent information about the local orientation and scale of image elements, but in the next downstream area, V2, cells respond more vigorously to stimuli containing naturalistic statistical structure than to matched control stimuli without that structure. The ability of human observers to detect naturalistic structure is well predicted by the strength of responses in V2, and the population representation in V2 also predicts perceptual similarity. Humans show BOLD fMRI responses that are consistent with neuronal measurements in macaque. Downstream of V2 the representation of true natural scenes becomes a more prominent driving feature of cortex. These results help to understand how information about elementary visual features is transformed into specific representations of scenes and objects found in areas higher in the visual pathway.