BROAD-TUNED CHROMATIC INPUTS TO COLOR-SELECTIVE NEURONS IN THE MONKEYVISUAL-CORTEX

1. Input mechanisms of 21 color-selective cells in cytochrome oxidase- rich blobs in layer II/III of the anesthetized and paralyzed monkey pr imary visual cortex were studied by an iontophoretic administration of the GABAergic receptor antagonist bicuculline methiodide (BMI). 2. Co lor-selective blob cells become responsive to originally nonresponsive colors of stimuli or brightness contrast stimuli during removal of in tracortical inhibition. 3. The magnitudes of the cells' responses to c olor stimuli during BMI administration were larger than the expected v alue of response calculated from the previously reported color tuning of color-selective geniculate cells and emission spectra of color stim ulus. 4. These results suggest that color-selective blob cells receive a convergence of different types of chromatic inputs and that intraco rtical inhibition confers selectivity for a given color on them.