[Functional MRI activation in area V4 alpha during a hue arrangement test].
BACKGROUND: Recent studies of cerebral information processing have shown that area V4 alpha, the area anterior to area V4, which is known as the human color center, is also associated with color. However, our clinical study has shown that lesions associated with hue arrangement test failures are more anterior than those associated with pseudoisochromatic plate test failure. PURPOSE AND METHODS: We studied area V4 alpha, and planned two functional magnetic resonance experiments for V4 alpha activity during the hue arrangement test. The task in the first experiment was virtual simulation of the hue arrangement test. The second experiment involved a task more specific to color information processing. RESULTS: We found significant activity in area V4 alpha in healthy subjects. CONCLUSIONS: We have reported that one of our patients with a more anterior lesion excluding area V4 had dyschromatopsia, as revealed by a panel D-15 test. Our experimental data and the clinical findings suggest that area V4 alpha plays an important role in processing during the hue arrangement test.