Abstract
Abstract: :
Purpose: To measure how selective the responses of V4 neurons are for stimuli that differ in shape, but are matched along other dimensions (luminance, color, etc.), and that cannot be discriminated after V4 lesions. Methods: These studies were done with stimuli that consisted of a 4 x 4 array of oblique line segments, and thus, were closely matched in global properties. Discrimination of these patterns was tested by having monkeys decide if successively presented stimuli were the same or different. The patterns were presented, during controlled fixation, in different regions of the visual field. We first found that V4 lesions eliminated the ability of monkeys to discriminate these stimuli. We also studied the selectivity of V4 neurons during discrimination of the same stimuli. Results: Many V4 neurons showed moderate shape selectivity for these stimuli. The information in the response selectivity was sufficient to mediate correct discrimination based on the responses of only a few neurons. Conclusion: These results suggest that the discrimination of these shapes is dependent on area V4, and that V4 neurons have sufficiently selective responses to these stimuli to mediate the behavioral performance. Supported byt EY 08898, and P30 EY01319 from NIH.
Keywords: 621 visual cortex • 394 electrophysiology: non-clinical • 579 shape, form, contour, object perception