Illusory contours are an example of the perceptual grouping of local features into a global percept.
Images were acquired on a GE Signa 1.5T scanner equipped for echoplanar imaging with resolution of 1.5 x 1.5mm 2 . Stimuli were flickered at 4 Hz. Signal intensities for each pixel were compared using a multistage statistical process to identify active regions. Specific regions of activity were observed in extra-striate cortex for the illusory contour condition and tended to be lateralized in the right hemisphere. We found areas in extra-striate cortex in which fMRI activity was correlated with the perception of illusory contours and, hence, perceptual grouping.