Progression of neuronal processing of visual objects.

We studied, with functional MRI, how neuronal processing for visual objects progresses in the human brain by measuring suppressive responses to stimulus pairs. Two concentric rectangular frames of slightly different sizes were presented such that the smaller frame was shown first, followed by the larger dominant frame, with interstimulus intervals of 0, 50 and 240-ms. The functional MRI response at 50-ms decreased along the ventral visual pathway. The response at 240-ms interstimulus interval was suppressed after a fusiform area at which the response at 50-ms interstimulus interval was highly suppressed already and the responses at 0, 50 and 240-ms interstimulus intervals showed a V-shaped dependence on those interstimulus intervals. These observations show a way of progression of the information processing along visual object recognition pathway.