Tuning of orientation detectors in human vision.
A new method to study the tuning of orientation detectors in the human visual system is proposed. The stimulus consists of a sequence of flashed sinusoidal gratings of random orientations and spatial phases shown at a fast presentation rate. The subject's task is to report, as fast as possible, when the presence of a particular orientation (horizontal, vertical, or oblique) is seen in the stimulus sequence by pressing a button. The data are analyzed by calculating the empirical distribution of orientations present in the stimulus sequence within an optimal time-window before the button was pressed. The resulting orientation distributions show a "Mexican hat" shape, which resembles the distributions obtained in some single neurons of monkey primary visual cortex using a similar method (Ringach et al., 1997). The findings are consistent with the idea of "lateral inhibition" between neighboring detectors in the orientation domain.
Center for Neural Science, New York University, NY 10003, USA.
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D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D008959:Models, Neurological; D009433:Neural Inhibition; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011601:Psychophysics; D011930:Reaction Time; D012399:Rotation; D014793:Visual Cortex / Q000502:physiology*