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Abstract:
The threshold for detecting a change in orientation away from the vertical of a briefly presented foveal line target is raised when there are immediately
following visual presentations. This masking effect was examined by measuring the capacity of a variety of patterns to act as masks. When patterns were made of
exactly the same number of light pixels, masking was least when they formed random dots and progressively became stronger as they formed lines of decreasing
curvature from full circles to straight lines. The longer the lines, the stronger the masking. Threshold elevation was highest when the masking pattern was spatially
superimposed on the line and was lessened when a large surround area was included, but there was still considerable masking when the interfering patterns were
confined to the surround. By placing masks and test lines in different eyes, or by giving them opposite contrast polarity, almost complete interocular and interpolarity
transfer was demonstrated. Relating these results to anatomical and electrophysiological findings about neurons in the primary visual cortex leads to the conclusion
that the masking effects could have their substrates in interaction between cells in V1.
